Social media platforms must restrict the use of personal data for targeted advertising, to comply with the bloc's regulatory law, the Court of Justice of the European Union ruled on Friday. The ruling comes as a blow to social media giant Meta.

Meta collects digital data of users of its social media platform Facebook when they visit other websites and use third-party apps, which allows Meta to personalize advertising. 

But under theEU's General Data Protection Regulation (GDPR), companies are obliged to adhere to the principle of "data minimization," restricting the amount and duration of data used for advertising purposes. 

What did the court say?

In Friday's ruling, the court declared that the aggregation, analysis and processing of all personal data without any time limit or distinction between the different types of data goes against the principle of data minimization. 

"An online social network such as Facebook cannot use all of the personal data obtained for the purposes of targeted advertising, without restriction as to time and without distinction as to type of data," the court said in a press release on the decision. 

In turn, Meta said it that it "takes privacy very seriously." 

"Everyone using Facebook has access to a wide range of settings and tools that allow people to manage how we use their information," the company said in a statement. 

Victory for Max Schrems

The challenge against Meta was brought on by Austrian privacy activist Max Schrems, the latest move in his yearslong battle against social media giants to ensure compliance with EU data privacy rules.

Schrems had complained that Meta's Facebook had processed personal data, including information about his sexual orientation, to target him with online advertising. 

The activist said that even though he had never disclosed his sexual orientation on his account, he publicly revealed this fact was during a panel discussion and was shown targeted ads soon after the event.

The EU's top court sided with Schrem saying that "a statement about [Schrem's] sexual orientation on the occasion of a public panel discussion does not authorize the operator of an online social network platform to process other data relating to his sexual orientation." 

"We are very pleased by the ruling, even though this result was very much expected," said Katharina Raabe-Stuppnig, a lawyer representing Schrems. 

"Meta has basically been building a huge data pool on users for 20 years now, and it is growing every day," Raabe-Stuppnig said. 

"Following this ruling only a small part of Meta's data pool will be allowed to be used for advertising — even when users consent to ads," she added. 

jcg/dj (Reuters, dpa, AP)