So, the online playtest has kicked off and been going strong for a little over a week, and I thought I'd give a progress report. We're still in the clan creation phase, but it's working out well. I was afraid that the online format might kill some of the collaborative goodness of the group setting crafting, but so far we've had lots of that nonetheless, which is really encouraging. Everybody's different ideas are inspiring and spinning off everybody else's, so I couldn't be happier so far.
In a similar vein, Google Wave is really useful for online RPGs. I'm totally sold. In addition to running this playtest, I'm playing in a friend's Big Eyes Small Mouth game, and it's going along swimmingly, even with jumping right into a combat scene. It tailors nicely to a variety of time frames for update availability, and easily supports people jumping in with contributions to different portions (the 'nested reply' option, which allows you to reply directly to a specific message in a wave, is particularly good for this).
After some more experience with both games, I'll probably post my thoughts on using Wave for online games, with some recommendations and such like, but for now, I say go for it if you have any desire to play traditional RPGs online.