[Tycho]

Personally I don't think wave failed to solve a problem for people, rather it solved too many problems for too many people. Like the article says it was hard to define. Google said it was email if it had been designed today, but email which is used for so many purposes (letters, discussions file transfer, chat, SMS, advertising, authentication, correspondence chess...) grew organically over a long period (I remember years ago email bugged me because I felt it purpose was unclear). Google needed that kind of organgic growth accelerated. But who knows, it might still happen..

Incidentally I can see something like Dropbox picking up a few of Wave's features.