Generally, Facebook offers an useful, fun and at least for now free means of communicating globally permitting exchanges using text (including Chat), pictures, and video. I dislike, but can understand, that it seems not allow exchange of such things as those same photos and videos by Fb users to those outside of its domain; I've wished to both save on my computer and email to non-Fb users videos from Friends which I'm either prohibited from doing, or am simply not smart enough to figure how (any help?). Additionally, many other online activities cannot be utilized without a Facebook account (and revealing its details outside of Fb, including Friends list) which apparently is increasingly the preferred method for validating the authenticity or the identity of an individual ostensibly to prevent untraceably fraudulent or simply uncivil postings in the case of Huffington Post online comments/responses on articles. At least for me, this has only diminished my participation in those other communities or services. While anonymity can be a shield for cowards and other bad actors, it can also be a shield from harassment, or worse, by those individuals. Having said that, I enjoy - make that appreciate - the fact I can impose my own limits on who is able to see my Fb postings and, to a somewhat lesser degree, eliminate unwanted trespassers.
It took me years to finally sign up for Facebook and I'm more enjoying it than not.