It’s a pointless solution for a problem that doesn’t even exist.
A simple combination of a common server and Outlook/Entourage is more than enough to keep a perfect mail-and-document history. People (and especially companies) have no business in using an online tool (by Google, so potentially unsafe as well) that resembles something of a downsized forum/chatbox.
That said, Google is aimng their arrows at way too many markets, and they’re making powerful enemies by doing so. If they keep it up this way, I won’t be surprised if they go bankrupt in 2-3 years. Though I think they’d rather quit with these pointless things (Android, Wave and Buzz) and keep doing the things they were doing “right”.