Google has taken the wraps off of its new lightbox ad format, “the first of a new family of display ads that allow marketers to pay only when a user engages.” These lightbox ads first appear on a page as a standard, scalable display ad. But after a cursor hovers over the ad for two seconds, the ad expands to a larger canvas. Google says that in tests, this hover feature eliminates nearly all accidental expansions and boosts engagement by 6-8 times over standard click-to-expand ads. This is presented as a win-win, as users will engage only with ads they want to see and marketers will pay for only truly engaged views. (Inside AdWords)