I know you don't have time to watch this mind-blowing demo about how Google guys have reinvented email with built in real-time, collaboration tools, playback, intelligent spellcheck, IM, social sharing and publishing tools - But you really, really really should. As you wont I put this link to the inside peek as well: about wave
However nothing is as good as seeing them run through their product - you do really come away thinking - 'wow - this is world changing' - if you a geek that is... Awesome.
The 'replay' function - where you can watch a thread develop over time is a-maz-ing.
The publish to a blog and live update is amazing
The simultaneous translator tool is amazing
The contextual spellcheck (yes, 'contextual') is amazing
The live-multi-editing tool, drag-and-drop photo sharing, instant inline forms & polls, mobile formating, embedability (I don;t think that's a word but... amazing)
Who knows if it will all work? - and who knows if we'll use it? It may crash and burn. But I love that they've dreamt this crazy utilitarian masterpiece up - it is a working vision of the power of HTML5.
Oh - and it's all open source - the actual app code for everyone to make their own versions - for free. Of course.