Wave is one of those things that doesn't necessarily seem that amazing, until you use it. Now, that's a total cop-out and pretty unfair besides, so let me take a crack at explaining why I think it's so amazing.
First, it's a total rethinking of a fundamental communications tool. Even in its most sophisticated current incarnations, email is still the same basic technology that it was when it was created 38 years ago. Even instant messaging isn't really that sophisticated, from a technological standpoint (of course, implementations and add-ons and all the rest are very complicated, but the underlying technology is old). Wave is different - it's a system that is only technologically possible because of the cloud concept, it literally couldn't have existed a decade ago (even though the cloud is a very old idea, of course).
Second, it's so open. Read more in our blog post about what I mean by that - open source, on top of an open platform and an open protocol. In order for this to get any kind of mass adoption, let alone take advantage of the productive chaos of millions of developers and thousands of great ideas, it needs to be this open. But making great things open isn't always something companies are comfortable with, and I'm glad to see Google is.
Third, it's designed from the ground up to be as collaborative as possible. Here's why you'll actually love using it. Let's say I'm a speechwriter working in an office.
Phase One: Email and locally-hosted documents. Every time I update a draft of a speech, I email a copy to seven different people. Each one reads it, marks up their draft and sends it back. I have to manage EIGHT copies of the same document, merge changes as I see fit, and send it back out. For them to mark up again and send back. For me to merge.
Phase Two: Email and cloud-hosted documents. Now, everybody's working from the same draft. But let's say there's a paragraph that contains a controversial position. We still have to email back and forth, eventually come to a consensus about the language, and then insert it into the document, where we can all mark it up. Better, but what if the document gets updated during the email discussion? Since the two things - email and document - are separate, they can fall out of sync very easily. And god forbid you try to add anyone to the discussion after the fact - they'll have to scroll all the way up to the top and read each email in sequence, while consulting the most recent draft and keeping track of the difference.
Phase Three: Wave. I write a speech as a wave, and add my 7 contributors to it. They make changes directly in the wave, which everyone else sees instantaneously - while the changes are being typed. If someone doesn't like a paragraph, they can add a comment directly under it, and a discussion springs from that comment. If someone makes a change to the paragraph, everyone can see it immediately. If someone comes in late to the discussion, they can just hit the replay button and see the conversation and the speech evolve.
There's a whole lot more to Wave, and I'll be happy to talk more about it later. But I'm really excited about it, and I can't wait for everyone to be able to use it and get as excited as I am!