Yeah, comparing it to Google Wave probably is a bit too much. In my neck of the tech woods HipChat is still pretty hip. I suspect that by the time we discover Slack, something else will have taken Slack's place as the new wave. Meanwhile I'll just keep visiting the same IRC channels outside of work that I have been frequenting for a decade. Will Slack be around in 10 years? Maybe. Will it be the poster-boy of internal chat? Unlikely.