Willi's got a bit in his blog about some prototypes we're working on. This one is meant to show on-scene disaster workers walking around assessing damage with gps and camera equipped mobile devices.
I messed with Croquet a bit yesterday. just out of interest, and also a bit because I was miffed at Second Life for deciding to bring the grid down yesterday. Such is life on the front end of the hype curve!
Second Life is more like the web, it has the chaotic, random feel that comes from random exploration, searching, and inputs from your social/professional network. Croquet has more of a self-contained, peer-to-peer feel. Right now I see Croquet as a targeted application development platform. I also see Croquet as lending itself to more abstract presentation. I really love the metaphor in Croquet of jumping through portals to navigate to new worlds! I'm quite sure I've only scratched the surface on Croquet, but it seems less collaborative, and more about cool new metaphors for information. In other words, I don't feel as much immersion, or presence of myself or others in the Croquet demos, but I do see more of a free-flowing, abstract experience.
That's not a knock, I see different horses for different courses. I'm even more of a Croquet noob than a Second Life noob, so take everything with a grain of salt. I've got to dive into Blender and Squeak, I think, before I really have a good grounding on the potential of Croquet.