Well those plans were made back in 06, so obviously the list of beta testers, and likely the rest of the list of guys willing to help is outdated.
I'd imagine when we are actually somewhere near ready to release a beta, then some more detailed plans will be made. If it is a closed beta, which certainly has some advantages, like allowing us to ensure beta participants are active, and not just there so they can play the game before anyone else, but actually know how to give good beta test feedback, so that a future public beta/release would be more stable.
A public beta requires much more server resources, will be more difficult to manage, but allows for the greatest variation in systems, which allows more things to be fixed. As Paul is dedicated to not just abandoning it after release, it isn't like all bugs must be fixed in beta or they will stay that way.