If you remember from the movie the Social Network, Mark Zuckerberg (played by Jesse Eisenberg) describes how people are on facebook because its cool and their friends are on there, but if their friends start to leave they may leave resulting in a chain reaction that eventually reduces the site to the next friendster or myspace.
I have noticed a lot of people leaving facebook, though like quitting a drug many actually comeback after a week or so. I have a ton of respect for those who leave and notice they tend to be cool, individualistic types and also often young professionals who are too busy to care about something as shallow and pointless as facebook. Adding to this is an increase in old and young people joining, more ads and commercialization and timeline.
Still, facebook is simply too big - over 600 million users - and popular to leave anytime soon. Every company and organization uses social media for marketing and PR now. Marketing jobs in social media are really popular among young professionals. Plus for every cool person who leaves 10 are overly involved i.e mainly attention *****s and betas who comment on and like everything while constantly updating you on their exciting lives with updates and photos. Wow great your drunk at a bar, im sure that was a precious memory you needed to capture and share because you'll probably never do that again.
I want to give up facebook, but mainly just to show everyone im too good for it and cause its a waste of time. Kinda a shallow reason, but atleast im honest and smart enough to recognize this. I probably wont though because its a good way to stay in touch with people and look-up coworkers. Plus it comes in handy now and then with girls (especially when they see all the cute girls i've partied with) and learning about events.
I've always been fascinated by facebook from a sociological standpoint. Like how a scientist might observe the rise of antibiotic resistant bacteria... then use it to get laid.
Honestly the majority of facebook is just a bunch of people lying to each other and themselves about their motives and reasoning for all their shallow behavior on the site. Watch girls get their pic taken at a bar. How often was that done before facebook? Its just a way for people to feel better about themselves and create the impression they are cool and interesting. Too bad no one worth knowing cares