I used to keep a list of people I wanted to be able to remember and stay in touch with. On paper. For most of them, I had no phone number, street address, email address, nothing-- only a name, and a desire to have some kind of contact again in the future. I was fairly certain I might never be able to track some of them down again.
I don't need the list any longer. Those people are all on Facebook. There is no other single place I can easily reconnect with them, let alone see how they're doing and what they're thinking without having to interrupt them and ask them to set aside time for me. I consider this pretty vital to my quality of life, and have no replacement for it.
Does it suck that one corporation owns this experience? Sure, in an abstract sense, but for the time being, there is no alternative. And thus far, there is nothing negative about it for me other than 'data which could potentially maybe be used against me somehow in the future'. I don't really share anything other than neutral/positive moments in my life, and I don't seek out anything other than how my old friends & extended family are doing. So I'm quite okay with it.
People have been hating on it and loudly deleting their profiles for many years. If they posted a bunch of stupid crap, I guess I could see why. But that seems to me like a problem which is easily avoided.