After two-months of fence-sitting, Illinois Governor Pat Quinn today signed controversial legislation requiring Internet retailers like Amazon.com and Overstock.com to collect Illinois’ 6.25% sales tax if they have affiliate sellers in the state. House Bill 3659, the Mainstreet Fairness Bill, was passed by the state’s lame duck legislature in early January. Since then, the bill has been the subject of fierce lobbying by traditional bricks and mortar retailers, who supported it, and Illinois-based Internet-only businesses, who warned that if Quinn didn’t veto it some of them would flee the state. Had Quinn done nothing, the bill would have become law tomorrow without his signature.