Shopping websites have ways of getting you to do what they want, and the sneakiest design and interface tricks they use are known as “dark patterns.” According to an extensive analysis from Princeton University and the University of Chicago, dark patterns appear on more than 11% of roughly 11,000 shopping sites studied.

These patterns are pervasive enough that US lawmakers have proposed a bill to ban certain varieties. But for now dark patterns are perfectly legal, even though they can fool users into giving up personal data, leverage compulsive behaviors in adults and children, and even lead to financial loss.

Losing interest already? Don’t go! We want you to stick around on this story, in part so you can see all the ways we can make you stick around (within the bounds of user-experience design, of course). Just to kick things off, what if we told you this article was only available for a limited time?