RMS says yadda yadda, so what?
You can advertise on Facebook, post events, etc. I would not recommend you to put any private data in there that you consider do not belong to the eyes of Facebook or NSA or whoever that you do not trust.
This is kind of problematic.
In organization management --- not specific to "business" ---, particularly involving descentralized organizations with different managers each, this creates communication noise or action inconsistency. Of course each continent has its own culture, but I fail to see in European culture where having accounts in such centralized non-standardized full-of-JS-or-non-free-JS social network sites is considered a must.