Ever signed up for something without realizing it, or checkout out of an ecommerce website only to find you’re enrolled in a subscription program? It happens to the best of us.

Confusopoly (aka Dilbert’s confusopoly) is an economic and marketing term referring to a purposeful act by a seller or group of sellers to confuse the buyer in order to ease the sale.

These dark patterns trick unsuspecting users into a gamut of actions: setting up recurring payments, purchasing items surreptitiously added to a shopping cart, or spamming all contacts through prechecked forms on Facebook games. These dark paterns just aren’t on the web, the The Columbia House mail-order music club of the ’80s and ’90s is a perfect example.

London-based UX designer Harry Brignull has documented it. Brignull’s website, darkpatterns.org, offers plenty of examples of deliberately confusing or deceptive user interfaces.