I'm guessing the relationship Meebo has built with its customer base is more important than the technology.

I've been using the (old) Meebo Messenger for years. I've never had the impression that they cared about its users a lot. There were no updates on the user interface since I began using it, they didn't add features that were highly requested on the feedback forums.

The toolbar thing is just... I don't know what that is. Looks useless to me.

Another thing, are there any good other web based multi messengers? I guess they will shut this down soon then?

I'm pretty sure they gave up on the messenger, and decided to put all their effort into the toolbar.