An interesting theory about why Google’s forays into social media (e.g., Buzz, Orkut, Wave, etc.) tend to be tonally wrong. “What’s the main difference between successful Google applications (search, maps, news, email) and a successful social applications? With Google applications we return to the app to do something specific and then go on to something else, whereas great social applications are designed to lure us back and make us never want to leave.
Subtraction.com: Why Google Cannot Build Social Applications