Related: Has anyone seen a company (besides Google) enable Google+ on their Apps domain and actually make use of it? Besides Hangouts (which technically works fine with Gmail and Talk enabled), that is.
I haven’t really. We use Google Hangouts at my regular employer, but nobody uses G+ for anything. I mean, yeah, everybody circled everybody when it first came out, but it’s never used.
I suspect at least part of the reason for that is part of the same reason FB@Work will find limited use - it doesn’t connect to anything else that people use to get their jobs done.