I've recently been trying to expand my knowledge of different continuous integration tools, and one that I stumbled upon is DamageControl.

I haven't used the software yet (because I don't have the time to play with it), but there was something on the site that I read that was both obvious, yet new to me.

They have an online book about Build Patterns, and while most of the book isn't completed, the one chapter that has some content in it talks about the difference between a fast build and a full build. Both builds create the same software, but the fast build is designed as more of a smoke test, and only runs a subset of unit tests, and those change over time as different areas of the system are worked on. The full build runs all unit tests, and if it ever fails from a unit test, that test gets automatically added to the fast build. That's a very cool idea, but I wonder how hard it would be to implement, and how big your projects have to get to justify the complexity.

Oh yeah, they also have a feature matrix comparing a few CI tools. It provides a pretty good run down of what each product supports.