"Who am I?" - reading thoughts and no fraud (see source)

Who Am I? uses "advanced advances in neuroscience" to determine the hobbies of any person. For a true analysis, it is enough to perform a simple procedure: in random order, click on all the red squares in the array.



And then press the “done!” Button

Clicking on the squares - just a trick to distract attention. In fact, the site uses the old focus with the definition of visited sites. Each cell is one of the popular sites of different thematic categories. The browser changes the color of the box, if such a site is in the history of surfing, following the instructions of the pseudo-class CSS : visited . The user clicks on the red square - so the authors of the "test" will find out what sites are in the history of surfing.
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Source Code Who Am I?

A similar technique is used in the game " Asteroids ". There are real and fake asteroids. The real ones can really bring down the ship, but the fake ones can not, they are displayed or not displayed on the screen, depending on whether the user has visited the corresponding site or not. If a user clicks on a fake asteroid, then he sees it. If not clicked - it means, does not see.

The collection of personal information occurs through user interaction, although he thinks he is playing a game.