How should email threads be ordered?

Question

I thought I had the answer to this question. If you view raw email, you can see that the most recent email is at the top, with the rest below in reverse chronological order. I think it's fair to say that most people perceive email that way. That's also how most email clients approach it, except Gmail that is.

The Gmail approach is the opposite, it has the latest email at the bottom of the thread as well as the reply box, more akin to how comment threads traditionally work:

What could be the reasoning behind that and what are the benefits/downfalls of either approach?

Answer 1

Users typically want to see the most recent activity first. Think tweets, online banking transactions, news updates. It makes it easy to see what's new since you last checked.

With conversations, it's different because there is the context of whatever message came before and after the one you're looking at. It's a similar situation to what you see in comments sections on blogs or Facebook. Moving replies to previous comments to the top of the list doesn't make sense, because the comment is out of context and may make no sense on its own.

A good example of how this works well is with bulletin board software. The posts with the most recent activity are typically at the top of the list. When you go to the detail view, the original post is at the top and newest at the end. It reads like a conversation, just like gmail. Usually it's easy to skip past the messages you've read to the first one you missed.

Outlook and other email applications don't completely ignore context, they just rely on the user scrolling down to see the text of the previous emails, in a slightly less readable format.

Meanwhile, like you mentioned, Gmail takes the conversation approach and actually hides that text that Outlook relies on. It's still there if you click on the "more" button, but why bother when you already have the context of the previous emails directly above?

The important part is having conversation context. After that, it comes to preference. Google is betting people prefer the conversational approach, but lets you switch back to the 'normal' sort order if the user prefers.

Answer 2

Let the user decide because everyone is different.

From the User Experience standpoint this can be tricky. If you have a very long running discussion then you have to navigate down through the whole thread until you reach the part that you're looking for. Since English speakers read from top to bottom this is somewhat intuitive, but it can be quite time consuming. Because of the nature of e-mail, most messages contain the original text in response, so you may end up reading the same pieces of the message over and over.

Google refers to it's threaded view as "conversation view." Since most discussions happen from top to bottom this is intuitive in that context. Thunderbird also works this way in threaded view even if you select to sort based on dates the other way. It simply sorts the thread containers, but not the messages underneath.

Most e-mail applications (eg. Thunderbird, Mac Mail, Outlook) allow you to reply above or below your conversation thread in each e-mail message depending on your preference. They also allow you to sort your messages based on the order in which they were received. With that being said, in-message they are allowing you to sort based on the agreed upon habits of you and the person you're interacting with. If your mail client sorts in a different way than the person you're e-mailing it is quite confusing to figure out what happened to the now non-linear thread.

Ideally, once you're inside of a thread you should be able to sort the thread so that you can see the most recent message first (without scrolling) if you wanted (Google doesn't have this option). This way you do not need to navigate all the way to the bottom of the thread. Also the latest message should contain most of the threaded discussion in order anyhow. Since this is the case, Google allows you to collapse to the most recent.

If this is a running log or conversation you should be able to sort however you want.

Answer 3

I am trying to remember which email service other than gmail and office outlook groups emails with the same subject line.

That said, the reason Gmail might want to show the latest email at the last is so that the user can scan through a long list of related emails and quickly get an understanding of the starting of the discussion and its current state as he scans from top to down.However if the order was in the reverse, then he would not use the natural scanning motion and would have to go to the oldest email at the bottom and slowly read up.

Of course, this might fail if the email thread is super long and you have to really scroll to the bottom to find to the bottom and a feature to quickly bring the latest email to the top would be helpful (Here is a link to a similar feature request on the Google labs forums which talks about the issues faced with threading). However Google does try to circumvent by allowing the user to collapse all the previous conversations to quickly get to the latest email.

Answer 4

Conceptually I would say that seeing the emails from oldest to newest makes sense because of how we keep archives in the real life - but let's look at a couple of use cases.

Use case 1. If you are cc'd in a thread and you need to get up to speed, having them chronologically makes sense and it's easier to understand the timeline of events - when and how the conversation moved.

Use case 2. You are active in a conversation - constantly replying and generating questions -and if not much time has passed- you will remember what the other person was saying without having the need to read the other messages. In this case, the newest email at the top is the best approach.

By comparing these two scenarios you can see that depending on the use case and the environment you can decide what is better practice.

Also keep in mind that office emails move much faster than personal emails. In an office you can have threads that are so long that if you put the newest at the bottom then you would have to scroll endlessly for each email and take away a few seconds of the user in each thread.

Google's solution to this problem was:

1. Allowing users to turn it off
2. Collapsing and expanding the messages: which works much better than an outlook solution that would add the newest at the bottom.

So I would say that if you have a feature like the collapse/expand feature, then you can have the newest at the bottom (if you decide is best for your users), but if you have no "user friendly feature" and the emails will just concatenate one after the other, then definitely the newest thread should go at the top.