Spot on. Exploiting the unfortunate growing narcissistic tendencies of our culture. It has some utility, but like anything, if you use FB, be wise.
I don't use my fb much and I agree with the marketing you are the product thing however it has put me back in touch with people from back in the day who I am happy to have back in my life. Conversely some people I never want to talk too again keep trying to be my friend. Devils advocate here, our internet swell info persona's and their words could also be viewed as part of swell info's product used for marketing purposes in the same manner as fb.
Pretty much my feelings on Facebook too. Don't really post very often anymore. I never post anything political, religious, controversial, or anything like that on there. I wiped every post going back years that had anything of that nature. Sometimes I'll post a picture of something, but not often. I just keep it around mainly to get in touch with old friends or for them to get in touch with me. My real friends know the kind of person I am, so I don't need to show a certain persona to the world.
Speaking of Facebook...how about the dudes that have a combined page for them and their wife? Man that's just as bad as carrying her purse behind her in the mall. And for the record, I'm a feminist.