what is google wave?

At this time it's by invitation only, kind of like how gmail was when it first came out. Here's a 7 minute overview.

Official details: Google Wave is an online communication and collaboration tool that makes real-time interactions more seamless -- in one place, you can communicate and collaborate using richly formatted text, photos, videos, maps, and more.

A wave is a conversation with multiple participants -- participants are people added to a wave to discuss and collaborate on its content. Participants can reply any time and anywhere within a wave, and they can edit content and add more participants as a wave develops. It's also possible to rewind waves with the playback functionality, to see what happened, and when.

My version: If you have any need ever of sharing a map, a photo, editing a document, chatting with multiple people about a project, etc. Google wave is a pretty cool tool that will allow you to do that.

I have 16 invites left.