A dark pattern is "a user interface that has been carefully crafted to trick users into doing things, such as buying insurance with their purchase or signing up for recurring bills". User experience designer Harry Brignull coined the neologism on 28 July 2010 with the registration of darkpatterns.org, a "pattern library with the specific goal of naming and shaming deceptive user interfaces". More broadly, dark patterns supplant "user value...in favor of shareholder value".
Patterns
Bait-and-switch
patterns advertise a free product or service that is wholly unavailable or stocked in small quantities. After announcing the product's unavailability, the page presents similar products of higher prices or lesser quality.
Confirmshaming
Confirmshaming uses shame to drive users to act. For example, when websites word an option to decline an email newsletter in a way that shames visitors into accepting.
Misdirection
Common in software installers, misdirection presents the user with a button in the fashion of a typical continuation button. A dark pattern would show a prominent "I accept these terms" button asking the user to accept the terms of a program unrelated to the one they are trying to install. Since the user typically will accept the terms by force of habit, the unrelated program can subsequently be installed. The installer's authors do this because the authors of the unrelated program pay for each installation that they procure. The alternative route in the installer, allowing the user to skip installing the unrelated program, is much less prominently displayed, or seems counter-intuitive. Some websites that ask for information that is not required also use misdirection. For example, one would fill out a username and password on one page, and after clicking the "next" button, the page asks the user for their email address with another "next" button as the only option. This hides the option to press "next" without entering the information. In some cases, the page shows the method to skip the step as a small, greyed-out link instead of a button, so it does not stand out to the user. Other examples include sites offering a way to invite friends by entering their email address, to upload a profile picture, or to identify interests.
Roach motel
A roach motel or a trammel net design provides an easy or straightforward path to get in but a difficult path to get out. Examples include businesses that require subscribers to print and mail their opt-out or cancellation request.
Research
A 2019 study investigated practices on 11,000 shopping web sites. It identified 1818 dark patterns total and grouped them into 15 categories. One publication from 2016 and another from 2017 document social media anti-privacy practices. The Norwegian Consumer Council published "Deceived by Design" in 2018, a report on deceptive user interface designs with popular social media platforms.