Well, well. According to this BBC story (which itself is based on a Financial Times story), Facebook is moving in on LinkedIn’s territory:

Facebook is building a network for professionals to connect and collaborate on work-related documents, the Financial Times reports.

Facebook at Work will look similar to its existing social network, but users will be able to keep their personal profiles separate, the paper says.

They also would be able to chat with colleagues, build professional networks and share documents, people said to be working on it told the Financial Times.

This is a difficult one for some of us. I mean to say, I loathe and detest LinkedIn, which I think is one of the most obnoxious ‘social’ networks I’ve seen. On the other hand, I’m not too enamoured of Facebook either. But I’m not surprised that LinkedIn’s shares were down today after the news broke.

In a more detached frame of mind, there might be something interesting here in terms of network theory. For example, are the ties that bind Facebook users stronger or weaker than those that link LinkedIn users?