Lexical

If you use facebook and don't have the facebook blog on your feed reader, you really should add it. It's massively useful for keeping track of the latest bits and pieces of development. It's only updated once a week or so (and seems to have a delayed-reaction over RSS), but the features it points out are usually fantastic. We've seen reactions to application spam and privacy concerns, introduction of wider political views, friends lists, links to other web 2.0 sites, and now the latest widget, the facebook lexicon.

This allows you to produce a display showing the number of times particular words and phrases appear on people's walls throughout facebook over time. So you can see how often the phrase 'new year' appears, or compare it to 'christmas' and 'easter'. It's not particularly useful for statistical analysis (except, obviously, of the words people use on facebook walls), but it's a fun tool and you can produce interesting results.