This looks like the most promising successor. Unfortunately it does not look like you can embed a collaborative pad or share it via a link. You need to register an account, go through Mozilla's website, and actually use the command line to join up. Why a website has a command line is a little beyond me!
Bespin definitely does not have the same sort of "just start editing a shared document" user interface that etherpad does. That isn't really our primary goal.
As for the command line: I really wish TextMate had a command line. I truly think the command line is going to be one of Bespin's fantastic features (though I'll agree with anyone that it is not a replacement for other nice bits of UI).
I'll point out that I doubt that amount EtherPad's purchase matters to a MOZILLA editor team and that the project being from Mozilla provides at least some guard against obscurity...
The guys who were really pushing Bespin forward went to Palm several months ago. The project looks great, but it may not have the same velocity right now.
Ben and Dion left in September, just before we kicked off the "Bespin Reboot" project, which we had been planning since mid-summer. I believe we'll soon have much better velocity than we did previously, thanks to our work in the Reboot. (Reboot is not a rewrite, but a very significant rearrangement of the code.)
