I avoided Facebook for a very long time for some of the reasons mentioned thus far. I was somewhat :bash:ed into joining by many as they felt it was an effective means to get the word out in regards to live streaming of pool -- something they knew I am very passionate about. Anyone that has ever seen my wall there can attest to the fact that my account is, "for the most part", strictly dedicated to that end. It has produced some good results, improved the hit count on many streams, and garnished some new stream links ... but it also has taken up lots of what little valuable time I have left on this "blue cue ball" (world) of ours.
Has it been worth it for me? In terms of promoting the aforementioned streams to lots of people in a timely and efficient manner: yes. In terms of being able to interact with "true friends/people I personally know": with a few exceptions -- no (I mostly use email, Skype, and the cell for that.).
Facebook is just another tool for me to accomplish an end which is, as mentioned, to promote our sport via the live streaming of same! I will continue to "primarily" use it to that end. If it stops producing results then I'm out of there!