Facebook privacy challenge attracts 25,000 users

Max Schrems has already caused Facebook to change its policies in a separate dispute

A data privacy campaigner has signed up 25,000 people to a "class action lawsuit" being taken against Facebook.

Max Schrems alleges that the way the social network monitors its members' activity on and off the site puts it in breach of EU laws.

As part of the claim, he also alleges that the company co-operated with Prism, a US surveillance scheme.

Facebook has previously denied knowing about Prism before it was mentioned in leaked US government documents.

The company has, however, acknowledged complying with national security requests from US government agencies.

Facebook has not commented on the wider case being brought against it.

The BBC understands it does not plan to respond until it has been served the relevant papers.

Facebook search

Mr Schrems asked Facebook users based outside the US and Canada who wished to take part in the case to sign up via an app.

Facebook's Graph Search feature is one of the facilities being challenged

The case is targeted against the company's Irish subsidiary, which is responsible for all accounts belonging to users outside of North America. It has been filed with the Commercial Court for Vienna, the 26 year old's home city.

Among the allegations are that Facebook broke EU privacy laws by introducing:

• Graph Search - a facility allowing users to find out about other members' activities on the social network
• External website tracking - monitoring members through the Like buttons embedded into third-party webpages
• Big data analysis - the ability to gain insights into Facebook members' by data-crunching the billions of interactions people have with the site every year

Model case

Mr Schrems is demanding 500 euros ($667, £396) in damages for each of the first 25,000 people who signed up to the case.

While the Austrian legal system does not make provision for US-style class actions, Mr Schrems is working round this by getting the other participants to transfer their financial claims to him, which is permitted.