Facebook recently announced a new enterprise-focused version of its social network, Facebook at Work. The features will include document collaboration, employee news feeds and profiles and the ability to build a professional network of contacts. Facebook is still a free platform (and right now, Facebook at Work is as well. They're also touting the fact that it will be ad-free), so those who use it personally might gravitate to it for that sole reason. Most businesses will probably still shy away from functionality issues, a lack of control and no option of owning your own data.