It's my turn to call out Hacker News now. How did a submission from 2009 that isn't really relevant now as it was in reference to comments made on Hacker News back in 2009 make it to the homepage? I'll sit back and watch people bite though. And for the record, I know there were numerous clones of SO made. Probably not in a weekend, but come on, the hardest part about Stack Overflow isn't how it is coded, it's scaling the site up for the millions of views it probably gets on a daily basis. You can build a clone of Stack Overflow using Wordpress with Buddypress, a Markdown plugin, JSON API plugin and the Cubepoints plugin.

Articles like this always make me laugh, especially when talked 4 years after they were written.