Well maybe not always...
Over the summer, I missed an important NY Times article on this very subject. So important, that I will now quote from it at length:
Four years ago, Stacy Snyder, then a 25-year-old teacher in training ..., posted a photo on her MySpace page that showed her at a party wearing a pirate hat and drinking from a plastic cup, with the caption “Drunken Pirate.” After discovering the page, her supervisor ... told her the photo was “unprofessional,” and the dean of [the university], where Snyder was enrolled, said she was promoting drinking in virtual view of her under-age students. As a result, days before Snyder’s scheduled graduation, the university denied her a teaching degree. Snyder sued, arguing that the university had violated her First Amendment rights by penalizing her for her (perfectly legal) after-hours behavior. But in 2008, a federal district judge rejected the claim, saying that because Snyder was a public employee ..., her “Drunken Pirate” post was not protected speech.
...The problem she faced is only one example of a challenge that, ..., is confronting millions of people around the globe: how best to live our lives in a world where the Internet records everything and forgets nothing...
Well I have some succinct advice for everyone out there in cyberland. Until the legal system catches up with Internet technology - and who knows when and if that will happen - shut up.
Seriously, and I don't mean to be rude - I expect Gen Y to be clueless about not disclosing every iota of their personal lives on Facebook - but my observation is that pretty much everyone is saying too much, showing too much and sharing too much.
So watch what you say; it can come back to haunt you.