Combined with Google's demand that every thing be The Next Big Thing, any closed beta is basically doomed. It worked exactly once, for Gmail, and only because of longstanding widespread demand for a big reliable e-mail service. Everything else had its initial obsessive weirdos and was left to rot on the vine.
Google+ only survived so long because they desperately wanted to undermine Facebook.
In retrospect, wave did feel like an EEE attempt by Google on email, I am happy it didn't replace email, but Google wave's features have since spread to web app standards
I used it to generate a shit ton of policy documents in a hurry.
The company I was at was being staged to be purchased. We had Jack shit for policy documents. The company that was organizing our sale said they needed a wide range of formalized documentation.
I basically set my entire team up on wave. I threw up outlines in different threads and we all just went to fucking town writing policy. We would peer review, make suggestions on each other's policy read over stuff while we worked on our own things.
It's been quite a while so I might not be remembering correctly, but even though they advertised it as an application, wasn't Google Wave more akin to a proof of concept? I was under the impression they took that engine and incorporated it into their collaboration products like Google Docs?