Thanks to Facebook, this generation may well be one of the first to keep long term contact with their school friends etc.
When I was at school, once you left school it wasn't generally too many years till you moved house, changed a phone number, etc and started to lose contact.
Even once email etc arrived, people changed ISP's, or the ISP's went bust, etc and that contact died out.
But my kids still have friends that left their school years ago to go overseas, who they're still in contact with via FB, and here in the ACT, when you do years 11 and 12, you leave school to go to "College" to do them, and many friends end up in different Colleges due to the specialities they each offer, and yet they are still readily in contact through FB. Short of FB going the way of MySpace, or Bebo, or the like, this generation may well remain in contact for longer than ever before.
Now, whether that's a good thing or a bad thing is another matter all together.
I had added a lot of people just for games, and one woman seemed quite normal and genuine, so we got chatting, but then she told me my phone number and address because she'd looked me up in the whitepages online, that gave me cause to wonder, then she started getting weirder and weirder, and I put more space between us, that made her more strange, and in the end she sent a message to everyone on my facebook friend's list - including my daughters - saying we'd been in an online affair. As I deleted her profile, she'd turn up under other profiles that I'd also added for the game, she had dozens of fake profiles. Took quite a while to be totally rid of her. Now I don't have anyone on FB that I don't personally know, or know at least how and where I know them from if I haven't met them in person. Stupid thing is, if I'd been having an online affair, I'd hardly have done it from my real profile, but it took a fair while to get my kids and friends convinced the woman was nuts. Thankfully she was also in the US, so hopefully she'll not suddenly turn up on my door one day.