I haven't used Facebook for nearly a decade
I joined Facebook back in 2004 when its use was restricted to a handful of Universities. I've never considered it to be anything spectacular, but merely an example of a large, distributed relational database. I signed up only because most students at my University had signed up which made it very easy to see WHO was in your lectures, labs, etc. for the purposes of coordinating group projects, exam preparation, etc.
Eventually, Facebook opened itself to anyone with a *.edu e-mail (all students) and to the general public as it is today.
At one point (I think it was around 2005) they started insisting that all users provide their date of birth to use the service... I wasn't going to provide that personal information so I kept ignoring their nag screens. Eventually it got to the point where I was being nagged everytime I clicked on a link, menu, etc. At that point, I closed my account and never looked back. Since most of the people on FB I knew in real life, it was no great loss -- they simply continued to interact with me via e-mail, text messaging, my website, etc.
Today, I have no desire to use FB. I hear about it in the news from time to time, but it is generally always with regards to privacy violations, government spying, or unethical practices on the part of FB.