Heh, this made me think of it as a sort of "Internet gentrification". A new hip service/site starts getting into the mainstream, the lay people move in, it becomes adapted for the lay people, and what made it hip in the first place moves out and on to other things. Doesn't fit perfectly, but I think it's an interesting way to look at it.
This is something I've noticed for a long time. Many communities have this occurrence.
usenet, 4chan, reddit, world of warcraft, the "internet" itself etc.
Any networked service can fall victim to this pattern. The original community can quickly get displaced and drown in the wake of rushing users and the powers that be will respond to the will of the majority thus betraying it's original intent.