http://www.newyorker.com/online/blogs/j ... laden.html
Although often referred to as “ads,” these zinger spots aren’t really advertisements at all: most of them don’t get broadcast. They are simply videos that the campaigns post online in an attempt to shape the daily news narrative. A better name for them might be “bait.” The rational strategy for an opponent is to ignore them or to dismiss them lightly, giving the media little reason to cover them. But rather than doing this, the Romney campaign and its allies reacted in a way that was guaranteed to give the story some legs.