I'm not sure that an opensource version of StackOverflow would be as useful as StackExchange. Let's ignore the re-implementation issue, and assume that an open

I'm not sure that an opensource version of StackOverflow would be as useful as StackExchange. Let's ignore the re-implementation issue, and assume that an open-source clone appears by magic tomorrow morning. You still have the support problem. Anyone doing this as more than a hobby needs a supported solution. The reason to pay $xxx a month is so that you can outsource worrying about the site's maintenance and upkeep. The cost (in man-hours) of building such a clone would be dwarfed by the hours spent bug-fixing and performance-tuning and dealing with hardware/software issues. If the site is ancillary to your business (if it's your customer support site, for instance), then there's a lot of sense in letting someone else handle the support, especially if web software isn't your core-competency. At $1300 for a dedicated, hosted server, you're essentially betting that it'll require more than 12 programmer-hours/week ($15.6k/year hosted vs. $50k/year for the programmer) to maintain the open-source version and run the hardware. And you're betting that someone at Fog Creek dedicated to maintaining Stack Exchange is going to be better at it than whomever you lasso into maintaining it part-time.