My team at O'Reilly Research has been crunching the numbers on the rise of Facebook as application platform, and we've released a new report today, entitled simply The Facebook Application Platform.

The good news has already been widely disseminated: there are nearly 5000 Facebook applications, and the top applications have tens of millions of installs and millions of active users. The bad news, alas, is in our report: 87% of the usage goes to only 84 applications!