TV makers are constantly crowing about the tricks their smart TVs can do. But one of the most popular brands has a feature that it’s not advertising: Vizio’s Smart TVs track your viewing habits and share it with advertisers, who can then find you on your phone and other devices. The tracking — which Vizio calls “Smart Interactivity” — is turned on by default for the more than 10 million Smart TVs that the company has sold. Customers who want to escape it have to opt-out. In a statement, Vizio said customers’ “non-personal identifiable information may be shared with select partners … to permit these companies to make, for example, better-informed decisions regarding content production, programming and advertising.”