I've only recently started a FB page and it's only because I started painting a little while ago and friends wanted to see them. I felt uncomfortable emailing them to individuals because I thought they might feel obliged to say how good they were, but if they're on a FB page they don't have to say anything, or they can just do a "like", even if they don't...lol... I have all my settings very tight and no one, other than my friends, see anything. I rarely post anything other than my paintings because I just don't always feel comfortable putting my opinions out there in public and in writing.
However, I became interested in a few community type groups, where people tend to post their opinions about things, and I wanted to take part in them. So I started another account with a fake name which is set so only I can see anything, and I have no friends attached to it. So I feel comfortable having my say about things in an anonymous way - much like MM....lol....
It does mystify me though why you get some "friend" requests from people. I've had a few where I've had no idea who the person was and we have no friends in common. They're just random people who send you friend requests. I just totally block those people straight away.
TBH I really don't like FB. I find it very unwieldy and awkward to use, but it serves my purposes. I'm not so sure it is the way of the future. Think Myspace. I've heard it said that there are less people using it now than there used to be. Young people seem to now be using other things like Instagram, Snapchat and Twitter, and I'm sure there a many other things as well.
I've never used Twitter. A couple of times I started an account, but each time I started getting emails straight away saying there was an issue with my password and giving me links to reset it etc - all very dodgy sounding, so that put me off it totally.