I like that he mentions integrating with other systems. Some of the biggest productivity gains we've seen have come from chat bots, which interject useful information into the conversation. They can also respond to commands from users to do useful actions. Our API still needs some polish, but we'll be releasing it to the public soon. Internally, we have chat bots that notify us about svn commits, Google alerts, changes to any Trac ticket or wiki page, etc. I can't wait to see what all the hackers here do with it. :)
Communication tools like this really change the game, especially for distributed teams.
We're in open public beta right now. Check out http://shoptalkapp.com and let us know what you think. We always value the opinion of HN readers.