Michael Isikoff's story in Newsweek, pointing a finger a Karl Rove as the source of the Valerie Plame-CIA leak, includes this attribution:

The e-mails surrendered by Time Inc., which are largely between Cooper and his editors, show that one of Cooper's sources was White House deputy chief of staff Karl Rove, according to two lawyers who asked not to be identified because they are representing witnesses sympathetic to the White House.

While more descriptive than "sources said," Newsweek is using anonymous sources in a story about anonymous sources after promising it would go a lot easier on the use of anonymous sources.

And all of this stems from criticism about the Bush Administration's use of intelligence...er...sources.