It's a useful product. I'm actually surprised that the state of Stack Overflow clones isn't better. Although much of the value of SO comes from its knowledge base, the UI and organization and administration is nice to have pre-built. When I was looking around the top choices among open source/free were askbot (https://github.com/ASKBOT/askbot-devel) and osqa (https://github.com/dzone/osqa). There was also a plug-in for Confluence (Questions) and Answerhub (seemed to be the pro/paid version of OSQA). But none of them were as nice as stack overflow, which was surprising to me.