The official directory is at http://www.stackexchange.com/directory . I believe it's opt-in, but it's got quite a few sites.

Has anyone here used a free, open-source SO clone? Any thoughts on which are good or bad?

We're really just starting to get OSQA (http://www.osqa.net) to a point where we can implement some of the new features and improvements which we hope will make it most useful.

We invite you all to share your ideas about what you want and need in a Q&A community at http://meta.osqa.net or to submit bugs and feature requests directly into our tracker at http://jira.osqa.net.

The best hands down is OSQA the english CNPROG fork, written in python. See http://osqa.net and, for an example of the site actually running: http://meta.osqa.net.

The developers for OSQA are currently building a tool to import a StackExchange dump. Two thumbs up for simple migration!

There is also a promising one in ruby called Shapado.

For a comprehensive list, evaluating project health and pointing at demos, check out this StackExchange answer: http://meta.stackoverflow.com/questions/2267/stack-overflow-...

Thank you!

There's also a Ruby on Rails clone called Shapado: http://gitorious.org/shapado (a running example here: http://shapado.com/)

That's the best one =)

An alternative to rank/crowd source stack exchange sites:

http://buyersvote.com/categories/the-best-stackexchange-com-...

isn't startups.com a SO site? it's not listed

It is, yes.

I simply can't believe so many people are paying that exorbitant price tag ($1600 to $16000 an year) to have zero-profit niche Q&A website.

It doesn't make sense financially, and they could sponsor free software development of the already mentioned clones.

I'm pretty sure it is because it is in beta and free: http://stackexchange.com/pricing

Someone mentioned in another HN thread or a comment somewhere else that none of those sites are actually paying anything yet, so maybe they're hoping that by the time they have to start paying they'll be making enough money to make it worthwhile.

A few site owners have indicated that they will be paying for StackExchange, but I suspect you're right that most won't.

http://meta.stackexchange.com/questions/4118/will-you-pay-fo...