Elizabeth Warren could be a formidable challenger to Scott Brown as Massachusetts senator. And today, she made another move toward becoming a candidate by filing paperwork to form an exploratory committee allowing her to rake in donations and volunteers, The Boston Globe reported. She also created a simple website that offers a place for supporters to sign up for updates. If Warren does jump into the race (the Times previously reported that an official decision would arrive after Labor Day), she may have a lot of ground to make up against Brown. In July, National Journal reported that Sen. Brown commissioned a head-to-head poll showing him leading Warren with a 53-28 percent margin among likely voters.