We're still not entirely certain what Google Wave is for -- or even if humans are capable of comprehending it -- but we do know that we're super-intrigued by the idea of third-party extensions that hook into the fledging messaging platform, and it sounds like the folks in Mountain View are as well. Google's planning to launch both an extension gallery and extension store in the coming months, which would allow users to easily find, buy, and share apps for Wave. It's not clear how the sharing will work, or how much Google expects extensions to cost, but it's certainly an interesting way to capitalize on Wave's flexibility. Our first request? An extension to kill live-typing. Let's make it happen.