There are people who have FB accounts on which all they do is associate themselves with family and friends and saying hi, but never posting anything other than replies. This is perfectly ok to do, but this can be accomplished far easier and more discreetly with email as often those replies contain dangerous geographic information. This is a patently obsolete way of seeing the web and it's purpose for mankind. This also glaringly misses the point of the social networking phenomenon.
FB is, as the first* Next Big Thing to blogging (followed by the pure descendant Twitter), a forum for airing all of those things rattling around in your head. Its a place to share those things that you just want to go out into the middle of a parking lot and scream for all to hear. to share the moments of Wow I just saved a bundle on my car insurance :) or solved some stupid computer issue that i know a lot of other people have. to truly foster humanity in the realm of "computers are sooo impersonal and you can't build relationships online, only in the physical world".
[* (non-crapped-up - re: MySpace was here first but it is completely USELESS for this unless you're a 12-16 yo teener or a perv looking to pick one up)]
Facebook and it's contemporaries are the last bastion of an environment in which corporate is merely a peer rather than an authority. In which subversion by big $$$ is only doable if the big $$$ is on the same page with what people want. Signing on with a belief system, or not, is entirely voluntary and much more likely to be done with a clear head and rational thought. It's less likely to brainwash if the recipient of information has the power to simply click it away (see Big TV Advertisers -vs- TiVo/DVR technology :) - scares the hell out of 'em because people don't have to watch ads any more. ).
[Anecdote - I don't watch ANYTHING on live cable or broadcast TV anymore because of this. Of course I don't equate PBS with "cable or broadcast TV" in any way.]
I just wanted to stand out in the facebook parking lot and shout this :)
Public Service Announcement: DO NOT USE INTERNET EXPLORER!!!! Definition: MySpace [Mai' thpathe] (pronounced with a lithp), N. - 1. A shrine to Terrible teener web programming, the worst M$ driven Web2.sl0 has to offer.