Iterations, a new internal app for managing what we work on next

That looks like it could allow extending a practice common in only fairly new startups to more mature and larger organizations. I like the idea of people being able to find things that they want to work on and that they think are important, build teams around themselves and take action. Particularly at the beginning of projects, things work better that way if you've built the right team. Later, you tend to get more pressure from external drivers and end up resorting to "business owners" prioritizing backlogs or whatever applies to your implicit or explicit SDLC or methods.

At first blush, this looks like a way to extend that useful aspects of new teams further by increasing the bandwidth for tracking, communicating priorities and dynamically organizing without losing things. That's how it is different from bug trackers, etc., mentioned in the other comments. It would be interesting to use something like this in a project as mature as 37signals and see what happens.

I will look into it further if it becomes a product.

Haven't ticketing systems and bug trackers been around for a long, long, long time?

That's funny, I actually use Basecamp for this right now. Specifically with the To-Do lists. I've never really had a problem with keeping track that way, interesting that they wanted something more dedicated to the task.

That being said, if they offered this as a product I'd get on board.