In a comment to a nostalgic utterance by Louis Gray, I found that Joelle Nebbe (iphigenie) expressed best what happens when participants in online communities move on :

“That’s the problem of online communities – they cannot move. It doesn’t matter how good the community is now, people just wont agree to move to the same place as one… They fragment, people move, new ones form, but large groups just never manage to move as one to a new platform. You get fond memories, and happy surprises when names reappear on another community later”.

The proverbial cat herding is well known to anyone who has had to deal with human change management, but in online communities not bound by any organizational structure the problem is even worse.

Online communities will continue to rise and fall, and with that there will always be fond memories and happy surprises !