A quiz on Facebook that displays a user’s most commonly-used words in a cloud image has been taken by over 17 million people. The New York Times reports that the quiz, like others titled “What do People Talk About Behind My Back,” and “Who Are the Hottest Friends Around You,” are among hundreds of quizzes created by South Korean company Vonvon. The quizzes, however, require users to log in before proceeding.

Online security experts are calling quizzes like these “privacy nightmares.” A post on Comparitech, an Internet security site, broke down what aspects of a user’s account are accessed by the quiz. Permissions allow the word cloud to see what is listed on public profiles and friends lists, and pulls data from a user’s timeline to create the final cloud image.

The terms of service on the quiz allow Vonvon to store a user’s data for any length of time, in any part of the world and with a third party. The post recommended that users stick to Buzzfeed and other services that do not require a log-in.

Jonghwah Kim, chief executive for Vonvon, says that there is not much that they can do with the data obtained by the quiz. Kim has stated on multiple occasions that Vonvon does not store personal information and that they have “nothing to sell.”

Some say that the data obtained by the word cloud quiz is nothing compared to the data that is gathered by Facebook without taking a quiz.