What's taken them this long? Facebook is finally getting into search seriously. Business week has a useful overview of the story in case you'd like to take a look.
So what does this all mean for the information professionals? Quite simply - a huge amount. In order to help people, and to advise them, we need to be where they are. That's less and less in the physical library - it's not even on the website now, it's going to be in Facebook. Like it or not, you will *have* to have a Facebook account and profile, so that your users can find you and link to you. Then you can start 'liking' pages, creating resources within Facebook, engaging in conversations and so on. It also means that the days of blocking Facebook are (probably) numbered, as it's going to be impossible to use the internet properly without it. I say (probably) since there are still enough stupid places that block access to the second largest search engine in the world - YouTube - because they don't understand it.
If you don't have a Facebook account - get one. If you do, consider creating a professional account as well, and think how you're going to work with colleagues and other professionals, and how that's going to differ from your friendship groups. While you're at it, tell your company that they'd better start paying a lot of attention to Facebook in the future.