Among my other emails this morning was finally an invitation from Google Wave. I had applied for Google Wave a couple of weeks ago, so at first it seemed exciting to get the invitation. Turns out that I wasn't so special after all. apparently throngs of people had received the same invitation over the weekend and some hadn't even applied.
Wave is an interesting concept. It's sort of a cross between email and chat, social media and collaboration. After kicking the tires for a bit, I found it to be useful tool, but nothing earth-shattering. Conversations (known as waves) are kept as lists. People participating in each conversation can update it and the updates are visible to others in real-time.
Each user is assigned an email with the address firstname.lastname@example.org, but it cannot be used to send or receive emails to/from external users. That's one feature that would make the product more useful. At this point I think Gmail is still a more robust service, but Wave is a work-in-progress. At some point Google may decide to integrate it with Gmail.
As Wave matures and as more people jump on, it has the potential to become a valuable tool, as many other Google products have proven to be. We'll see.