I'm not moaning about it because it isn't worthy of even a small groan.
I'm sorry it isn't the same thing. I was doing forums when the rich fb brat was still wearing nappies. He came along much later said that he had invented something much cooler/better than forums and that we should all sign up. I looked at facebook, found nothing of interest and moved on.
I did sign on to Google+ which allows me to communicate privately with my family and friends. Seeing that G+ allowed you to do that, facebook then "invented" that for its users too about 18 months later.
Facebook has its uses. I've been using it for years and more recently, I have found it particularly good for sharing club information. I set up a page for my regional hot-air balloon club so that we can share our plans to go flying, update land owner information and discus airworthiness and training issues. The same goes for the running club to which I belong, we publish our individual plans to go out running and meet up with others for company, publish club night training schedules and a host of other things.
It works very well, and although a forum can be used for these things, I find Facebook is geared more towards the social interaction which is associated with a club or society. Twitter is also a very good source of information.
They clearly harvest your browsing data and sell that to advertisers. For example, I have recently been looking for a suction cup to pull the front panel off my iMac computer. Spookily my Facebook page is now littered with adverts for these devices. Well that's how I explained it to the wife.