The network assigns thousands of interests to its members so that advertisers always have an audience available, according to a new scientific article.

The interests of users are one of the most useful ways for advertisers to choose their audience on Facebook. People interested in “Caribbean” and who “travel frequently” are more likely to see Dominican resorts. It’s an apparently useful service because it offers ads closer to the user’s experience: “We’ve designed our ad system to show fewer ads irrelevant (which is one of the big complaints [of users]), “Rob Goldman, vice president of Facebook ads, said on Twitter on Thursday.

But the company, according to a new scientific article, stretches the interests of users until their value can be diluted. The average number of interests per user is around 300 and 350. But in the 10% that have the most interests assigned, they range from about 1,000 to almost 9,000. At the other extreme, the 10% that have less interests, sees in Facebook ads related to less than 50 preferences.

Along with the overprofiled, the results give two other very interesting data: one, there are about 9% of users who see more ads than the rest. And two, for advertisers who extend their campaign infinitely, the probability that a user clicks on an ad grows very lightly the more ads it receives. That is, the ad that is most likely to receive a click is the first.