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.
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.
