[Loopy]

One interesting difference i see between Facebook & Twitter is that i've never seen someone being peer pressured into signing up to Twitter whereas i see it constantly occur for facebook. I too share the 15 year olds position, i signed up to twitter but hardly anyone i know in real life uses it and i'm not interested in celebrities.

[carbon8]

From the relatively external POV (I don't care for facebook), this is just the 3rd round of the social pressure thing, the first two being friendster and myspace. Facebook is the first one that has really also dragged in older generations, but that's not enough to prevent it from ending up like the others. Sure, there's no obvious single replacement on the horizon, but the networks have switched platforms en masse twice before and there's no reason to believe they can't again.

In fact, now that all generations are getting acclimated to the concept of social networking, some of those new people will almost certainly start looking beyond facebook, and with interoperable web services this could result in at least a good chunk of the social web increasingly using focused components rather than one monolithic system.