ok... so it's like a forum kinda? I don't really get this sofar

Well, from what I gathered it is like taking the basic principal of a forum, and of e-mail, and of instant messaging and mixing them altogether while at the same time expanding on them.

At parts in the video they mention that the majority of the source code for Wave is open, so what they are trying to do is completely change the way people communicate by spreading and ultimately replacing our normal methods with one all inclusive one.

The best way I can think to describe it is that instead of e-mails or IMs, there would be waves which not only function identically to both, but also can include as many people as you like, branch off at anytime, be embedded just about anywhere on the web, and with the code being open will be able to be improved on endlessly.

They demo a couple of the addons already written for wave in the video, and after seeing them I cant help but wonder if eventually this could also do away with sites like myspace and facebook.