WARNING to political candidates: the Internet isn't always your friend. Ask John Edwards, Democratic presidential contender. He had hired a pair of progressive women bloggers, thinking they'd help buff his street cred as the plain-talking advocate of liberal policies. But past writings by the pair were never fully vetted and contained insulting posts on Catholic leaders and policies. After two days of cogitating, Edwards tried to finesse things: He was offended by the writings, but wouldn't fire either one. Bloggers, hired or not, are creeping ever closer to the center of the political ring. They bring huge followings, unfiltered views...