In this June 11, 2014, file photo, a man walks past a mural in an office on the Facebook campus in Menlo Park, Calif. Facebook is taking an aggressive new tack that blocks ad blockers on the desktop version of its service, insisting that well-made, relevant ads can be "useful." At the same time, the world's biggest social media company says it is giving users easier ways to decide what types of ads they want to see. Unless, of course, the answer is "none." (AP Photo/Jeff Chiu, File)