For me, Facebook has been evidence of social networking coming of age. Not to come off as a fogey, but "I was there when it all started." In the past, I made some new friends online whom I've valued for nearly 2 decades, and I was lucky to reconnect with a couple people I'd lost contact with along the way through life. But the thing is, all the people I connected with online in the 90s or even the early 2000s were pretty geeky - a lot of lost old friends remained lost.
The real good that FB has done for me is as the vehicle that *actually works* to reconnect me with some favorite, far less tech-savvy people from every stage in my life. Several things had to shift to change that:
1) The online population had to reach a critical mass. Not just getting email accounts, but also becoming "present" online, which means building a version of themselves via providing information.
2) Tools had to get friendly enough for Grandpa Joe and Auntie Luddite to be able to use them. The tools we used in the 90s were primitive and non-intuitive, and presented a huge barrier for the vast majority of people.
3) Revenue had to be reachable in order to pay for the programmers and other creators required to make those tools. Plenty got built by hobbyists and academics back in the day, but the results were, as mentioned above, only friendly to geeks.
Facebook costs a bunch of money to run and evolve, but it is "free" for us to use. The cost to all of us users is the information we trade for access to all the tools and toys and people that we get to play with on Facebook.
Here's the thing I think it all boils down to for me: I am responsible for what information I put on Facebook.
Through some clever algorithm, the ads I see on the edge of the page as I surf FB are relevant to me. I see more ads for snowboards and training conferences and mountain vacations and bands I like than I do for diapers or dating services or motorsports or whatever ads YOU see. I see that as a benefit! (and again as a businessman, hooray for effective targeting of ads!)
I'm not a pollyanna about all this. Someone I grew up with no doubt has a photo or two that would embarrass the hell out of me if they posted it. Some stranger might learn a little more about me than I would share with them in the physical world.
But my friend asked - is it worth it? The way I'm using it, most definitely.