Having your siblings friend you on Facebook is one thing, getting poked by your parents is something else.
Then your boss comments on your weekend activities and Facebook's ubiquity gets a little creepy. It's not a new observation, people have been bemoaning Facebook's lack of domain separation ever since the platform expanded from college kids to the general public. It was then that the aforementioned co-eds realised their booze fueled girls-gone-wild party-pics might not play so well when they got friended by the CTO at their graduating 'first choice' investment bank.
Clearly just not friending these people won't work -- the solution, of course, is silos -- an invisible barrier that lets you put each friend in the right bucket. Friend. Family. Workmate. Then each posting / app / status update only gets pushed to the people who should be seeing it. It's perfect but it also adds complexity. Facebookers rarely go to the trouble of rotating portrait photos in their photo albums, you think they're going to think through the implications of each status update and photo post?
But what's worse than information leakage? Your mother uses Facebook. That's not just an insult my friends, that's death for any online application that values 'cool'. Trendy stores keep unwelcome adults out by playing loud obnoxious music and strobing their lights in a way sure to induce seizures in anyone over 30. MySpace works pretty much the same way. Part of Facebook's problem is its elegant design, the same feature that has helped its monumental growth may now be encouraging too many people to join.
How long before the sheer uncoolness of a social network your parents are part of and your boss reads daily leads hipsters to seek out a less 'parent friendly' alternative? Then again, the propagation of vampire-werewolf-ninja-pirate 'apps' might be enough to distract nosy parents and employers from the incriminating kegger photos.
Facebook wants to win market share from LinkedIn, but maybe we'd all be better off if our social networks and professional networks kept their distance.
It's hard to argue that a social network's astronomic growth is a bad thing. But how Zuckerberg and his increasingly talented team are going to deal with these issues should be of supreme interest to those looking to invest in Facebook's estimated 15b valuation.