Google Wave has been heavily anticipated and widely hyped. It has already spawned detractors and been ridiculed as the Segway of email. I think these people are nuts. Google Wave represents a whole new way of thinking about communications. Google Wave itself may or may not live up to these grandiose expectations, but the ideas that Wave is popularizing will.

1. Messages are a thing now. In the old world you’d send an email, they’d reply, CC-ing someone new, you’d IM, they’d IM. Where are these messages? Various copies exist all over and none are necessarily definitive. With Wave the message exists in the cloud and there is a single, version-controlled master copy. This is huge.
2. We have a handle on time. The “playback” aspect of Wave means that you can easily visualize the change of a document over time. This means you can drill down into the meetings notes document and see all of the items and discussion that took place to arrive at the final document. It embraces the concept that documents are dynamic, whether we intend them to be or not, and so adds a temporal dimension. This allow discussions to turn directly into documents.
3. Real-time is where it is at. Wave makes instantaneous collaboration a reality. This is huge. Simultaneously editing and discussing documents means we will find ways of collaborating that literally have never existed before. Proposals, meeting notes, agendas, todo lists, shoppings lists, strategy documents — all of it will be more fun and more efficient because of the ease of collaboration in Wave.
4. Wave brings things together. Here is an example. A customer emails about a problem. It spawns two internal discussions, one a technical issue and one a business issue. These issues are discussed over email and IM and the outcome is a policy document, a technical HOWTO document and a reply to the customer. All of this can take place inside of Wave quickly and easily. Instead of flurries of emails, IMs, drafts and edits of documents in 3 or 4 applications, it all takes place in real-time in Wave. All participants can see as much or as little of the discussion as they need to. 
5. It’s open and extensible. It’s open source, so you can run your own copy and have complete control of it. Gadgets and Robots will make it possible to integrate Wave with the enterprise and the marketplace. 


If all Wave did was these 5 things, it would be amazing, but this is just the tip of the iceberg of what is on deck from the Wave team and I think it will literally transform online communications.