At first I wondered how in the world would something like this even work. Then I realized Facebook wouldn't be selling conventional TV ads, it would be ads for set-top boxes. Facebook has wanted to get its hands on TV ad budgets for years. Now it’s taking another step closer, by selling ads that will actually appear on TVs. Next week, Facebook will start delivering video ads on apps that run on set-top boxes like Apple TV and Roku through the company’s ad network. Facebook is partnering with two publishers, A+E and Tubi TV, and will deliver ads to people who watch videos on those apps, on actual television sets.