That is presuming you are still actually looking. If you look at this article from O’reilly you will see that while the number of subscribers are increasing the number of active users is slowly declining. Meaning that more people are falling off the site than are joining. If I take a quick poll among my peers this matches what is shown on this graph, that a lot of them have fallen away from Facebook use. The number of useless applications that are available continues to grow.
As reports over the last day or so are suggesting a number of Facebook shareholders (mostly employees) are trying to realise some equity for their stake now, presumably while it retains some value. The company seems to not be using its initial advantage to build a sustained business model yet and there is obviously some more work for them to do. While the promise of the social network that incorporated third party application integration was high, this is yet to translate into something that is actually useful.
The problem could be that Facebook simply grew to fast. During the fast growth they made quick decisions on philosophy and technology. While the site continues to need more work to expand its utility these changes are hugely more complex and difficult to implement while providing support to their existing users. While new functionality could help the site over time it could alienate some users or disrupt service which will annoy even more.
There is still promise in the philosophy but it is losing some of the market impetus while they work out how to turn promise into reality. I would imagine that some of the larger investors will be pushing for some experienced business builders to be brought onto the team to help work out what to do.