I work in a relatively small company, everyone here has a private Facebook account, and I see no way in which Facebook chat is in any way worse than Skype. Both are closed-source, privately-owned, centralized servivces. But only one of them I tend to have opened anyway, as I use it to communicate with most of the people I know, and I can use it through Emacs when I find myself too distracted by the vanilla version.

I came to say the same thing. With a twist.

Using FB at work is one thing, using FB to communicate with your coworkers another. FB is 'private' for me (as funny as that sounds - there's nothing really private on FB of course, but it's the social life outside of work that I refer to here). Not corporate.