This is more on the experimental side of "research" but I just finished a prototype realtime visualization of tweets that reference Wikipedia:
http://wikitweets.herokuapp.com/
wikitweets is a NodeJS [1] application that listens to the Twitter Streaming API [2] for tweets that contain Wikipedia URLs, and then looks up the relevant Wikipedia article using the API to ultimately stream the information to the browser using SocketIO [3]. The most amazing thing for me is seeing the application run comfortably (so far) as a single process on Heroku with no attached database needed. If you are curious the code is on GitHub [4].
The key to wikistream working at all is that Twitter allows you to search and filter the stream using the original (unshorted) URL. So for example a Tweet with the text:
Question of the Day: What’s the greatest seafaring movie ever? Some suggestions: http://bit.ly/IqsE1e (But anything on water'll work) #QOD [5]
Is discoverable with a search query like:
Question of the Day wikipedia.org [6]
Note "wikipedia.org" doesn't exist in the text of the original tweet at all, since it has been shortened by bit.ly -- but it is still searchable because Twitter appear to be unshortening and indexing URLs. Anyhow, I thought I'd share here since this also relied heavily on the various language Wikipedia APIs.
//Ed
[1] http://nodejs.org [2] https://dev.twitter.com/docs/streaming-api/methods [3] http://socket.io [4] https://github.com/edsu/wikitweets [5] https://twitter.com/#!/EWeitzman/status/195520487357558784 [6] https://twitter.com/#!/search/realtime/Question%20of%20the%20Day%20wikipedia...