That google maps thing was a HUGE eye-opener for me when I saw it a week ago or so. I had no idea the capability to request data like that existed in pure JavaScript. As soon as I saw that I sat down and built a VERY basic chat room using that same technology in about 7 hours at my local coffee shop.

I think Google is going to open a LOT of developers up to these ideas. Being able to break away from the whole request-->display-->enter data-->request-->display cycle can be huge, and hopefully we'll begin to think of web pages more as interfaces, instead of request results.