This site. http://efreedom.com is winding me up at the moment. It's scraping from stackoverflow and Google has it ahead in the serps for a fair number of search queries I've run.
I wouldn't mind so much, but a) the site isn't as user friendly as stackoverflow and b) obviously isn't updated with answers as fast as stackoverflow is.
Obviously I should just be searching stackoverflow directly, but I'm afraid that habit of going to google first is a difficult one to break.