There's a good demo at http://pivotaltracker.com http://pivotaltracker.com (registration required, though) All joking aside, this project probably will appeal

There's a good demo at http://pivotaltracker.com http://pivotaltracker.com (registration required, though) All joking aside, this project probably will appeal most to people already familiar with Pivotal Tracker, much like the Basecamp clones out there will appeal to people familiar with Basecamp, who either can't afford or don't want to pay for Basecamp. I don't think these kinds of projects really hurt Pivotal Labs or 37signals in any significant way, and can even help them in two ways: 1) having some competition to light a fire under their butts, and 2) often times when you use these FOSS clones you realize how much better and smoother the real versions are and go back.