Here at Stack Exchange we're currently wrestling with weaknesses in our tags system. As we open up new verticals – some of which include very non-technical users like cooking – we suspect that the concept of tags confuses new users. Specifically, we suspect that your average web user doesn't have an accurate mental model of how tagging systems work.

I have a long and conflicted history with tags. At my first startup, we started with tags and over the next couple of years removed them bit by bit (because of confusion) until we ended up with categories. And we didn't even allow users to enter categories themselves.

Is the concept of tags confusing for your average web user?

If yes, is the problem simply a naming problem (i.e. would "topics" or "categories" be easier to understand? Or is the problem more conceptual or mechanical?

If some users don't understand tags, is it realistic to educate new users about how the system works on first use, or is it something that requires some amount of engagement over time to grasp?

  • Not to be rude, but shouldn't this be in meta?
    – Chris Bier
    Commented Jan 21, 2013 at 21:21
  • 23
    I talked this over with the community team, and the consensus was that if the question is strictly related to the user experience site, then it should go in meta-ux. However, this is a question that applies to all of the Stack Exchange sites, and further if the question didn't specifically have the words "Stack Exchange", then it would be a general UX question and therefore be completely within the scope of the regular UX site.
    – Jeremy T
    Commented Jan 21, 2013 at 21:31
  • ah ok :) sounds good to me
    – Chris Bier
    Commented Jan 21, 2013 at 21:32
  • 5
    Personally, I pretty much ignored the tagging system in SE. When I need to search content, I prefer to use free text search (via Google, usually). I can understand the use of tag when you have nontextual content, like in image sharing websites, but in text-heavy sites like SE, I don't see why tagging would be useful and I've seen cases where it seems to be more of a hindrance, for instance many users in SO like to ask question about a specific language, but does not mention that language in body text, only in the tags.
    – Lie Ryan
    Commented Feb 20, 2013 at 14:26

9 Answers 9


I notice that the answers cover a slightly different field from what was asked in the comment by JonW:

Really, what I'm interested in is whether or not people know what they can do with tags after they've already been assigned - such as browsing the site using tags to find related content, as opposed to just tagging content with relevant tags.

so here's an answer which is more focused on the aspect of using tags to find an already tagged content.

Tags or categories?

Tags are inherently different from categories and especially allow to solve the uniqueness of attribution problem I've already illustrated in the black sleeping cat example. Users, on the other hand, are not always aware of this difference. When I asked people what is the difference between categories and tags, there was a lot of different answers:

  1. Categories are usually presented in a form of a tree; tags are never presented this way.

    Wrong. As categories may be flat, tags may be contained in larger tags which are themselves in other tags, etc. The similar approach is used by Adobe Lightroom with its keywords: while a photo may have several keywords (tags), those keywords may be organized in a form of a tree. Assigning a child keyword usually (depends on the settings) assigns the parent keywords as well.

  2. Categories are more general than tags.

    Wrong. Categories are exactly the same as tags; the only difference is that the same element may have multiple tags, but the same element cannot be in several categories at a time.

  3. Categories are used to group content, whereas tags are used to quickly find the content later.


    Both are used to group content. If I tag some of my photos my cat, it means that I have a group of photos with my cat on them.

    Both are used to quickly find the content later. When I put a file in G:\Development\<Project name> and another file in E:\Misc\Funny pictures, it's exactly for the purpose of finding the content easier later.

  4. Tags are used to indicate something about the tagged element; categories show that the element belongs to something.

    Wrong, or at least difficult to understand. When I tag a photo as Niagara Falls, it means exactly the same thing as if I were putting this photo in G:\Photos\Niagara Falls\ directory, i.e. that the photo has Niagara Falls on it, and that it belongs to the set of photos of Niagara Falls.

  5. Categories are mutually exclusive. Tags are not.


Conclusion: So, what do we get? We get that users don't really understand the difference between categories and tags. The worst of all is that they are expecting differences which don't exist, and that the differences they imagine may turn them against the usage of the tags.

How does it apply to search and filtering?

Search and filtering

There are basically three ways to search for content:

  1. Category-based searching,

    This is the basic form of search where the user remains passive. Tree-oriented structures are the most direct illustration of category-based searching. When I want to buy a new Xeon E5-2620 CPU on my favorite website, I go to:

    Hardware > Components > CPU > Socket 2011

  2. Meta-based and/or assisted searching,

    This search still assists the user, but enables the user to be more active. For example, when I want to buy the AF-S NIKKOR 70-200mm f/2.8G ED VR II lens, I may filter the list of every lens by specifying that I want to see only the lenses produced by Nikon, which are from 70 to 200mm and have vibration reduction.

  3. Free text searching.

    This search is the most permissive, since the user writes whatever she want. This is also the most powerful one when the user knows exactly what she's searching for and when search actually works (most of the time, it doesn't).

    For example, if I want to read the specs of Ford Fusion Hybrid SE, by typing Fusion Hybrid SE on a website which publishes vehicle specifications, I expect to see exactly the page corresponding to this model.

Many websites and applications allow several of those three search models. Often, tree-form categories-based content can also be found through a textual search, or there are tags and textual search at the same time, or categorized content can additionally be filtered with meta-based filters, etc.

This is done because of the simple observation: people are using the type of search they need in a specific circumstance. Taking again the black sleeping cat example:

  • The user who wants to find photos of black cats will simply use the tag cat and filter the images to display only black objects.

  • The user who wants an exact photo of a little black kitty having fun with a mouse will do a text search for black kitten playing with a mouse.

  • The user who just wants to spend the next hour studying specifications and gazing at the sexy photos of Socket 2011 CPUs will probably use categories tree.

The place of tags in search and filtering

Tags are weird, since they replace categories, but also belong to the second type of search: the meta-based one.

For the sake of simplicity, we can assume that there might be a difference between tags and metadata¹: metadata would be presented more as a purely filtering technique, whereas tags would be primary used for search.

For example, the size of the photo would be pure meta, used to filter photos to show only the large ones.

In this case, tags would present themselves as a search element which is used when the user wants to remain passive. Nearly identical to categories, especially when placed in a form of a tree, tags would still remain different from categories because of their non-exclusivity.

When categories are replaced by tags, users may not really understand that they should include multiple tags in order to focus their search to what they really need. This is exactly as the issue of some people when it comes to using textual search. For example when searching for the tickets price they need to pay to go on a trip to Switzerland, they may start by trying to type "trip" alone, or "Switzerland" alone.

Conclusion: categories, despite being terrible as a way to organize information, would be more intuitive for beginners in order to use assisted, passive tree-based search. On the other hand, a well-implemented tagging system should help the user to understand both:

  • The fact that the search may contain multiple tags.

    Clickable tags, as it is implemented on Stack Overflow, are a poor way to show that tags may be used together in a search, since the user will simply click on one tag, then, later, on another tag, and always get the results for a single tag.

    To avoid this flaw, Stack Exchange uses an excellent technique: to put the clicked tag in a search box. A slightly curious user will try to type other tags to finally find that tags can be combined to refine the results further.

  • And the fact that same level tags are not mutually exclusive.

    This can be done by showing multiple tags for tagged items, instead of simply grouping the items by tags. This is exactly what is done at Stack Exchange, where questions, even in their collapsed mode (on the home page or in the list of search results), are showing all their tags.

Ambiguous terminology

  1. While tags themselves are used more and more, the term tag may not be understand clearly. GMail, for example, uses labels which are exactly the same as tags.

  2. The word tag has also a different meaning, closer to identity, like in animal tagging.

  3. Finally, in web communities where tags are assigned by moderators, tags may be perceived more like an approval (example: tagging a message to appear on a home page) or a disapproval (example: tagging a post as off-topic).

Those three points make it more difficult for beginners to understand what tags are in an unambiguous way. When there is a risk of misunderstanding, designers should:

  • Either use a different term, such as label used by GMail,

  • Or redesign the interface to make it clear what tags are for, especially to disambiguate this term in a case where tags are assigned by moderators.

¹ Even if the assumption that there is a difference between pure metadata and tags makes things simpler, this assumption is highly questionable. For example a date would be pure metadata, but still, it may be used as a first-class search element, like when somebody searches for photos of 9/11 attacks. In the same way, tags are often used to actually filter the content, instead of searching.

  • 3
    Users might not agree with this assertion: "Categories are exactly the same as tags; the only difference is that the same element may have multiple tags, but the same element cannot be in several categories at a time." In Outlook, items can be assigned to multiple categories.
    – nadyne
    Commented Feb 16, 2013 at 5:52
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    @Nadyne Richmond: agreed, and the fact that some apps use the term categories when it's actually tags makes things more difficult then they are. Office website tells that "A category is a keyword or phrase that [...]": that's clearly a tag. In the same way, several French websites I know use the term categories when the exact term would be tags. Commented Feb 16, 2013 at 7:08
  • Wanting my site to be all French I wrote "étiquettes" (tags) but I think I'll go with "themes" now.
    – Manu
    Commented Feb 20, 2013 at 17:55
  • @MainMa, why do you differ between categories and tags? In my opinion, they are the same. What you are doing when you are tagging elements is actually categorizing the elements. And yes i've read your example regarding tree structures. I can agree that a tree-structure is a really bad way to display elements, but if you ignore that "categories has to be in a tree structure" - there is no longer an issue. Instead of differing, you can combine them. Use tags as categories / categories as tags. And why not just stop using the word tag, and start using the word category.
    – Velkommen
    Commented Dec 30, 2013 at 15:45

In What Drives Content Tagging: The Case of Photos on Flickr (Nov, Naaman, Ye, 2008), content tagging by a random sample of Flickr users is analysed:

We contacted a random sample of users, selected from a page of photos uploaded recently to Flickr, and emailed 1373 users an invitation to participate in the webbased survey. A total of 237 valid responses were received, representing a 17.1% response rate, much in line with similar studies. The average respondents’ age was 35.5 (median = 32), and 54.3% of the respondents were male.

They found that in the case of Flickr photos, social reasons were primary drivers for tagging content. Users tagged photos so that family, friends, and themselves would later easily be able to find and browse their content. This is made possible by the interfaces that Flickr establishes based around tagging, suggesting that tagging is successful when supported and exposed adequately by the underlying infrastructure.

I haven't found any similar research for a website like Stack Exchange, but it's worth considering that tagging here is less impactful on your direct social circles (eg. family and friends) and more a way of managing content for the community. As such there is no implicit motivation involved in tagging content; users likely tag content if they feel driven to organise the community, or perhaps if they're after a badge (explicit motivation).

None of this answers your question of whether users inherently grok tagging. However, it might help narrow down your question: rather than ask "do people understand tagging?" perhaps the question should be "What motivates people to use tagging systems? Are we implementing the right set of incentives to drive tagging?" I would probably initiate a similar user study amongst Stack Exchange users to discover what their motivation is and how to further incentivize them.

At the moment, Stack Exchange sites don't explain why tagging is valuable, or what you gain from doing so (other than "get a badge!"). There are many ways to surface feedback to users as to why and how their tags are contributing to the site and to the inherent usefulness of Stack Exchange to them directly. For instance, upon tagging a question, you could suggest to users that they can immediately subscribe to tags, which makes the tag immediately useful to them. Or you could show them a question in their tag when they visit the site and ask "is this tagged correctly?", etc. In any case, do the research and find out what people on Stack Exchange want to do around tagging. From there, you can extrapolate how tagging makes sense and what you can do to improve how the UI is communicating its value.

Here are some other papers you may want to look at, though you have to pay to get at them:


I had this exact problem about a year ago, and ended up doing a number of interviews to try work out whether it was clearer. What I found is by no means definitive, it is just sharing my experience.

We found that most people in our target group understood the concept of tags. A few understood them better as 'labels', which it seems they got from gmail. But using tags not only had pretty decent understanding, but it also seems to be growing as more applications use flat sorting with tags rather than a category system.

If you will only have one tag per item, I would suggest using categories instead, as they had a much higher understanding with no confusion at all (in our sample).


Thinking different

I would like to answer this from another angle, as I feel the straight up answer has already been given. The question implies that users are alone and responsible of their own content like this system was some unattended SharePoint Intranet. But it's not.

On all StackExchange sites, and on Wikipedia (which also uses tags) there are moderators and experienced users who help inecperienced users. So the use case is rather an inexperienced user asking a question and posting it on an .SE site. The system is forgiving and doesn't require tags. Later on, some helpful experienced user comes along and edits the question and adds tags. The user who first posted the question then learns that, OK there are tags. That's nice - I wonder what they do? Clicks the tag and finds out more...

So what we have here is a case of whether users can learn tags or not, as in understanding what they are. I'd say yes, in due time users will understand from experience, and with the help from other users.

The Facebook reference

We all have feelings of both hatred and love when it comes to Facebook, but since it is the system with the most users, I think it would be unfair, not to mention Facebook.

I'm turning 45 years in a few months and I looked up my mothers Facebook photos to see if there where any tags. And guess what, even my retired mother used tags in the images she wanted to tag. Also Facebook uses that exact word: Tag!. Proof of that is a screenshot of me and my daughter on Facebook in the process of being taged.

Facebook tagging process

Tag browsing

Users are well aware of the complexity of todays web applications and do know that almost every element can be interacted with. But that doesn't prof that users understand tagging, as one or several content filtering options. Tag browsing or content filtering is a fairly new concept, and inexperienced users probably doesn't know how to use them. If they knew - they would't be non-technical/non-web savvy users. So by definition in the question, inexperienced users don't use advanced concepts.

What about the future?

As we move along in time towards the future there will be less and less users not understanding how to fully use a web application in general. More specifically this is valid also for the tagging, tag browsing and content filtering actions. Users has to learn how to filter content rather than just navigating/searching for it. Filtering through metadata will be more and more important, and as a concequence, the user interfaces for filtering will improve and possibly create new web conventions.

If users want to take control over their information retreival in an even more information intense world they will be forced to learn new information retreival concepts. If not, they will probably be left behind. It is our job, as UX-practicioners, too see to that the number of users who are left behind are as small as possible.

  • 2
    This does illustrate that users are familiar with tagging their content, but does it show that users know what they can actually do once items have been tagged? You can navigate around content just using tags, you can find related items because of the tags... Is that something that typical users understand and use themselves?
    – JonW
    Commented Feb 15, 2013 at 15:19
  • @JonW added a section on Tag Browsing to adress your follow up question. More to come soon! Commented Feb 16, 2013 at 13:25
  • Users has to learn how to filter content rather than just navigating/searching for it I'd paint a different future Machine has to learn how to filter content for the user.
    – Lie Ryan
    Commented Feb 20, 2013 at 14:21

I'm pretty convinced normal users don't know what to do with tags per se.

The only really common place for tagging is Facebook - Google for 'do people understand what to do with tags' and 9 out of 10 first page links are all facebook related.

With facebook no-one really thinks about searching for a tag - because the tag is just a person. So you're searching for the person not the tag. So tags help to bring up relevant content when you're searching (typing in a search box, not browsing) for something but they wouldn't go looking for a 'tag'.

Perhaps, as in facebook, if the tags were specific things like 'people' or for Stack Exchange use 'subject' then people would understand to look up a subject or tag a question with multiple 'subject'.

So at the bottom of the page here you would have:

enter image description here


I'm not sure, tags can be confusing for some users and just useful for the others. In my opinion, you could switch the name to "keywords" and run an AB test on it.

Another idea is the editor mechanism. While typing in the question, some of the words could get backlit, as suggested keywords (I think it would be quite easy to build a dictionary, just a matter of time). Users then would be asked at the very end (with a dialog window or something) to kindly check off any of the suggested keywords they think is indeed relevant.

Sorry if this is not a direct answer to the question, just trying to go one step forward and find a convenient solution.

  • Not a bad suggestion about auto-highlighting potential tags while users are filling in questions. That might make people more aware of the whole tagging concept. I don't think I agree that AB testing a change from 'Tag' to 'Keyword' is the way to go about testing that though; it'd be hard to accurately measure anything because there is no actual 'conversion' to measure success against in the user journey of someone using tags.
    – JonW
    Commented Feb 19, 2013 at 8:42
  • Just wondering if Quora is inspired by your suggestion :) Commented Aug 29, 2016 at 16:37

Jeremy, the way the question is stated is a two-edged sword. It can be interpreted as

  1. "are users enabled to grasp the tags concept?", or
  2. "did we communicate the tags concept clearly enough in order for the users to understand it?".

As a UX type I lean to the second interpretation, which leads to self-criticism and enhancement opportunities.
To me, the issue is not if the users (we) understand it but how to communicate it.

Historically, internet sites had to "bribe" their users in order to get something back.
It's a fair exchange. The site offers something valuable and the users who want it abide by the site's rules. Like, for example, you surrender your email to get a white paper that looks interesting. Or, you agree to be banged by advertisements in exchange for the use of an email service. It seems that few people want to pay money for technical answers.

What has the StackExchange sites constellation that spells value for their users? Guess ...

You guessed well: reputation points!
If reputation earning was somehow related to good tagging, we'd strive for applying the best tags . So assuming that you bear with me in this idea, now the issue is how to pay for good tagging, which takes us to which tags are good or how to evaluate tagging.

Firstly, tags should be owned by the tagger.
Then, we might start the discussion by asserting that good tags are those that take the who are searching to what they are looking for. For example a user searches for *usability", gets a results list, and chooses several questions: those are successful tags and the users who set those tags are to be rewarded by a small amount, like 1/5 of a point.

In case you were still reading, here comes to mind the fact that this is somehow complicated for the user to understand. But now, given that SE is offering bribes, the users will want to listen. It would be enough with a simple "Learn how the right tagging can earn you reputation points" link, and a brief and clear explanation, to make the users tag conscious.

This idea is aligned with the Flickr findings: the users tagged pictures because of the additional value they could get from that tagging, like bragging be making their relatives know the fancy places where they have been, or whatever.


I feel that tags are an aid to community discovery more so than an organizational means for the user himself/herself.

In this case I think messaging to the effect of:

numerous but relevant tags = more relevant exposure for your question

...would be a strong and accurate motivator.

I think of hashtags (twitter, instagram etc.) as probably the most widespread and modern use of tagging and their use is usually to further exposure.

  • Please add some references to this answer, or else it's just your opinion, which I'm sure the OP isn't really looking for.
    – Rahul
    Commented Jan 22, 2013 at 1:03
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    Hashtag use is growing on social media and expanding to other services - thereforce 'tagging' is alive and well. en.wikipedia.org/wiki/Hashtag
    – Max
    Commented Jan 22, 2013 at 1:10

Actually, in my opinion, there is no big difference between "tags" and "categories" - generally speaking, both are some way to associate some set of objects (articles, questions, files etc.) with some logical structure that to allow easy navigation. In this association, the category or the tag is a "key" and the object is "content"

In both cases, one object can be associated with more than one key in the same time.

The great difference is that usually so called "categories" are ordered in hierarchical tree structure, while so called tags are not classified at all.

This makes tag implementation more flexible and easy for implementation, but does not provide the users with hierarchical search - what they are learned to use in other situations.

For example, the file systems are organized as "categories tree" and all users are familiar with this structure and are able to use it efficiently.

So, that is why all users are less trained to use "tag" systems and some learning time is always needed.

BTW, every categories system can be converted to tag system, by simply removing the tree structure and leaving the categories free in one big pool. The reverse is not possible, without recreating the lost tree structure.

  • " all users are familiar with this [filesystem structure] and are able to use it efficiently". Well, no. And the tablet generation will be even less familiar with filesystems.
    – MSalters
    Commented Feb 15, 2013 at 13:06
  • The hierarchical tree search structures are very wide spread in the RL as well. The human brain works by summarizing the objects and incorporating them into some hierarchy.
    – johnfound
    Commented Feb 15, 2013 at 13:20
  • @johnfound: "Unfortunately, hierarchical trees are one of the most inappropriately used controls in the toolbox. They can be highly problematic for users; many people have difficulty thinking in terms of hierarchical data structures.", About Face 3, The Essentials of Interaction Design, Alan Cooper, Robert Reimann and David Cronin, ISBN 978-0-470-08411-3, p. 457. Commented Feb 16, 2013 at 7:13
  • 1
    @MainMa inappropriately used doesn't mean its a bad, it just means a lot of people use it incorrectly, it also backs up johnfound's point of them being widespread (i.e. a lot of people use it)
    – icc97
    Commented Feb 16, 2013 at 13:40
  • 1
    @MainMa: Well, my statement was based on my experience. I never met normal people that have problems with well structured data. These authors maybe talk about some pathology?
    – johnfound
    Commented Feb 16, 2013 at 16:04

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