Co-op is a web app that combines Twitter, to-do lists, and chat for your group or team. And it’s free!

I think this is going to become very popular with small teams spread across teams. This is something Twitter should have implemented long ago.

The developers, Iridesco, are smartly leveraging this free app to drive subscriptions to their paid timekeeping app, Harvest. When you use Co-op, you can also enable timekeeping with a Harvest account.

(via swiss-miss.com)