[brc]

Nailed it.

Already I see awkward parent/child relationships. To the parent, they love feeling 'in touch'. To the child, it's just embarassing that their parents are hanging around on Facebook. As they move into the embarrassing photos/stories, they're either going to find a new platform or create a separate identity, or something, to conduct themselves online in private.

SMS was the killer app for teens because they could exchange messages with friends (a) cheaply and (b) without being overheard.