I will try to state some assumptions about your app, and work from there.
- There exists a set of physical locations (places)
- There exists a set of events, scheduled to take place at one or more
of the predefined locations.
- There exists a list of tweets tied either to an event (via hashtag)
or a place (via hashtag or geotag)
- There exists a list of people who produced the tweets.
If I understand your question correctly, you want to use some form of emphasis to indicate the "fun factor" of a location. Let's assume that you can derive fun-factor into a single number, where a large positive number indicates lots of "happy people having fun at this location" and a large negative number indicating lots of "people were disappointed and left this location unhappy". From your example thumbs-up/down icon, I assume the thumbs-up would be displayed for a positive number, and a thumbs-down would be displayed for a negative number.
So, in my opinion, your solution would have to take into account a couple of things:
- First, will you show the locations as some kind of list, or will they
be related spatially (on a map)?
- If there are many locations, will you automatically filter them (only
show "top 10 fun locations" within a 30km radius of the current
- If they are related spatially, and displayed on a map, how will this
influence your filtering? (what happens if I am at the Olympics, and
there are 35 events (sports, comedy, dining) happening within a 1km
radius at 20 different locations? Do you only show 10 locations with sports? Only for the top 10 sporting events?)
- What is more important: "locations", or "events"? Do you wish to emphasise the location, or do you wish to emphasise the type of event? Or both?
- Does it matter if the people tweeting about the events are linked
(social network "friends") with the person using the app?
- Do you take into account the preferences of the person using the app?
(for example, a person who enjoys classical music may not be
interested in a rock-concert, so they don't care if a lot of people
are having fun at the concert venue).
- How do people indicate that they are having fun? Do they use your
app? Do they have to use Twitter for that?
So, let's imagine a scenario: a well-known comedian is in town. He is touring with some rock-musician friends of his, entertaining the concert-goers at an after-party. I like comedy, but not rock-music. Some of my friends went to the concert, and are currently attending the after-party. They (and a lot of other people) are having a good time. People (including my friends) tweet about the rock concert. Other people (including my friends) tweet about the comedian. Your app needs to filter out the noise about the rock concert, and emphasise the stand-up comedy "event" at the after-party location.
The more filters you put in place (the more specifics you have about the user's preferences), the "easier" it becomes to show things visually using icons on a map. You may even consider scaling the icon/glyph, or changing its color according to the fun factor. Example: larger size glyph for more fun, smaller for less fun. Bright red for lots of fun, dark blue for unhappy people leaving (make sure to pick colours that are "safe" for use by colour-blind people, so try to avoid red/green). You may even show small Twitter-portraits of the friends that are at the location below the map (depending on screen real-estate), along the with the photos that are being shared (by everyone at that location right now)
If you have to use a list:
- Sort the list (fun places at the top - emphasise by position)
- Indicate "fun factor" by size (bigger/smaller font)
- Indicate "fun factor" by colour and luminance (blue/red,
- Try to use a graphic (icon) to indicate the type of event.
- Optionally try to attach your friends (via Twitter portraits) to the event (again, depending on screen real-estate this may be difficult). The more friends, the bigger the chance that the user will "have fun"
As to the design of the actual icon, this may be culturally dependant (this also applies to colour choice). I will start with something abstract first, and then depending on constraints (map/list/screen real estate) try to develop a solution that works when scaled/coloured (or both).
If you want to break down the fun factor into many different levels (not just a single number, but "level of noise" with "number of people" with "cost of event" as examples), and you want to communicate these different aspects of fun to the user, then this becomes trickier again.
I hope I have provided a starting point at least. Good luck.