Has anyone seen any non abusive sites pop up yet that makes use of the stackoverflow data dump?
I created SPWho2.com, a statistics analysis dump for StackOverflow. I built it so that I can throw in the database dumps for ServerFault and SuperUser when those become available too.
I'm super-anal about not being abusive with it. If there's anything that anybody wants to see added to make it more clear about where the real data lives, let me know and I'll be happy to implement it. I'm never going to show the question content or answer content on SPWho2 because I don't want to distract the search engines. Every author page and question name links back to StackOverflow.
I also created wiki articles about importing & analyzing the StackOverflow export over at SQLServerPedia. It's a SQL Server wiki, and I'm editor-in-chief over there. I put my howto scripts, sample queries, and tutorial videos there, including a tutorial video about mining the StackOverflow database with Excel's data mining plugins.