I've been beta testing Google Wave for about a month now, and... well... it's complicated.
I want to love Google Wave, because it's a bloody seductive premise, but it's just not intuitive enough for mass appeal. I'm one of those bleeding edge guys when it comes to web apps and I have a very hard time wrapping my feeble brain around Google Wave's advantage. I can't tell you how many folks I've been waving with who just throw up their arms and exclaim "I don't get it!". It's so hard to figure out, and life is so short...
And chatting via Wave is dangerous. Unlike every other IM that sends your message when you press "Enter", Wave sends each character over in real-time. Typos, mistakes and awkward pauses while you check your thesaurus or Wikipedia are fully exposed. It makes you not want to chat. How's that for improved communication?
Wave is supposed to be email were email invented today. It's very ambitious, but possibly too smart for its own good. Besides, Google has already re-invented email for the better. It's called Gmail.