Joel Spolsky and Jeff Atwood have launched their hosted software model – StackExchange – a while back now, and we’re already starting to see a plethora of sites building theme-based discussion Q&A sites using StackExchange as the engine. This is a collection of a few of the interesting StackExchange sites I’ve come across so far. I intend to keep building on this list with stuff I find useful as I discover more of them.

The “Trilogy” (This is where it all began) – StackOverflow, ServerFault, SuperUser
Databases – OracleOverflow, Ask SSC
Microsoft Office – OfficeQuestions
Security – SecurityCrunch

Startups/Entrepreneurship – OnStartups (by Dharmesh Shah)

In the meanwhile, there’s also a massive dump of StackExchange sites that seems to be fairly up-to-date.