You are tricked into publicly sharing more information about yourself than you really intended to. Named after Facebook CEO Mark Zuckerberg.
In its early days, Facebook had a reputation for making it difficult for users to control their privacy settings, and generally making it very easy to "overshare" by mistake. In response to feedback from consumers and privacy groups, Facebook has created a clearer, easier to use privacy settings area.
Today, privacy zuckering seems to take place mainly behind the scenes, thanks to the data brokerage industry. Here's how it works: when you use a service (e.g. a store card), the small print hidden in the Terms and Conditions gives them permission to sell your personal data to anyone. Data brokers buy it and combine it with everything else they find about you online into a profile, which they then resell. Your profile may contain information about your sexual preferences, physical & mental health. In theory your profile could result in you being refused services such as insurance or loans. The industry is currently not well regulated and it is very difficult to opt out of having your data brokered. See stopdatamining.me for more information. Though commonplace and extremely troubling, state-level surveillance is not considered a dark pattern.
The infographic below gives further details about the data brokerage industry (2015, webpagefx).