A bit technical for some Mashable fans, perhaps, but developers should note that Facebook launched Facebook Query Language (FQL) this weekend.
FQL is an SQL-style interface to access the data that you can normally access through their API. The advantages over the normal Facebook API include reduced bandwidth and parsing costs, a reduction in the number of requests necessary and a single unified interface for all of your data. There's a test console here that lets you run queries against your own Facebook account.
What could you build with this? This script claims to show a list of all your friends relationship statuses (are they single?), along with a percentage breakdown. We were receiving error messages with that script, but clearly there are lots of similar ideas that could be tried. If you build anything cool, let us know.
Related: Facebook-iTunes, Facebook-Jobster, Facebook Diaries