There is an interesting article on salon.com about how opposition aides place stories with blogs and reporters to discredit their opponents. "Oppo dumps" seems to be the new phrase to describe this. Often these "oppo dumps" are sent anonymously to reporters and blogs.
The whole McCain "Bomb Iran" story seems to have come about due to an anonymous "oppo dump" via the Drudge Report. And it appears that the Republican Presidential candidates are doing their best to court Matt Drudge.