From comScore Media Metrix, a report of campaign and political web sites experiencing the greatest gains in web site traffic of all measured categories:

“With both Republican and Democratic presidential debates swinging into action, the politics category saw a 17-percent increase to 9 million visitors in May, making it the top-gaining category overall for the month. Traffic to Politico.com, which sponsored the Republican Presidential debate on May 3, jumped 162 percent for the month to 648,000 visitors, while MoveOn.org’s traffic surged 246 percent to 689,000 visitors due in large part to an online petition against gas price increases. Several presidential candidate websites also saw their traffic increase, led by BarackObama.com (up 13 percent to 298,000 visitors) and HillaryClinton.com (up 3 percent to 217,000 visitors).”