It does sound interesting, although I have to admit I was one of those who thought it was a joke, mostly because it was like no other email system I’ve heard of and the press release seemed somewhat suspect. So, seeing as it is legitimate, what do I think?
While I probably won’t use it myself (I already have, theoretically, 1GB of email storage), something like this is a very bold step for Google and could set an interesting precedent. It will certainly turn the heat up on Google’s rivals and re-invigorate the webmail market.
But next time I hope they don’t announce something like this on April Fool’s Day.