Online shopping can be full of pop-ups and distractions, as well as some traps and misdirection. If you can find the Unsubscribe or Cancel button, even that tool might not release you completely. And that’s intentional. “Marketplace’s” Kimberly Adams speaks with Harry Brignull, a user-experience specialist based in the United Kingdom. He calls these design strategies “dark patterns,” and he’s been documenting them for over a decade.