I haven't really seen much of it, but I'm intrigued by the idea. That said though, I fear it might not exactly be the next gmail. It reminds me in many ways of the early Microsoft "Active Desktop" push, along with IE's "push" websites. Nothing caught on there until years later when RSS feeds finally took off. Wave seems like it might be useful, but only in the same way AIM is... that is to say, it only works if everyone is using it.
Anyway, thanks to a friend, it appears I now have some invites to hand out. So if you're raring to get your paws on the newest google noun/verb, lemme know, and I'll toss a few out here. If, on the other hand, all of this was gibberish to you, then don't panic... you'll likely never miss it. :-)
I haven't really bothered to read into it all that much lately, perhaps I should. Honestly, I wasn't all that impressed with gmail myself (I get more spam on gmail than I do on hotmail, sadly) and stopped using it. Primarily I just use my own server for things like that now, where I can just block the ip addresses of entire countries (keeping the list up to date). Funny how blocking Korea, China, and Japan seems to stop 99% of the spam I'd get.
Shiny http://en.wikipedia.org/wiki/Google_Wave#Etymology
The only real time collaboration I ever do requires me to be there in person. Although, I will be all over this as soon as I find out how to connect my foot to someones face through the internet.
There was a comic (I think it was CTRL+ALT+DEL) that said "I'm going to be rich as soon as I invent a device that lets you punch someone through the internet." or something like that. I tried to find it, but the closest I came was this...
http://answers.yahoo.com/question/index?qid=20080919194338AAkRB6o
http://bash.org/?4281
Ah yes, that was definitely it. IRC is way cooler than a comic anyway. :-)