Organisations that deploy Facebook's ubiquitous "Like" button on their websites risk falling foul of the General Data Protection Regulation following a landmark ruling by the European Court of Justice.
The EU's highest court has decided that website owners can be held liable for data collection when using the so-called "social sharing" widgets.
The ruling (PDF) states that employing such widgets would make the organisation a joint data controller, along with Facebook – and judging by its recent record, you don't want to be anywhere near Zuckerberg's antisocial network when privacy regulators come a-calling.
'Purposes of data processing'
According to the court, website owners "must provide, at the time of their collection, certain information to those visitors such as, for example, its identity and the purposes of the [data] processing".
By extension, the ECJ's decision also applies to services like Twitter and LinkedIn.
Facebook's "Like" is far from an innocent expression of affection for a brand or a message: its primary purpose is to track individuals across websites, and permit data collection even when they are not explicitly using any of Facebook's products.
The case that brought social sharing widgets to the attention of the ECJ involved German fashion retailer Fashion ID, which placed Facebook's big brother button on its website and was subsequently sued by consumer rights group Verbraucherzentrale NRW.
The org claimed the fact that Fashion ID's website users were automatically surrendering their data – including IP address, browser identification string and a shedload of cookies – contravened the EU Data Protection Directive (DPR) of 1995, which has since been superseded by much stricter General Data Protection Regulation (GDPR).
In 2016, Fashion ID lost in a Dusseldorf regional court, and appealed to a higher German court, with Facebook joining in the appeal. The case was then escalated to the ECJ, with the outcome closely watched by law and privacy experts.
On Monday, the ECJ ruled that Fashion ID could be considered a joint data controller "in respect of the collection and transmission to Facebook of the personal data of visitors to its website".
The court added that it was not, in principle, "a controller in respect of the subsequent processing of those data carried out by Facebook alone".
"Thus, with regard to the case in which the data subject has given his or her consent, the Court holds that the operator of a website such as Fashion ID must obtain that prior consent (solely) in respect of operations for which it is the (joint) controller, namely the collection and transmission of the data," the ECJ said.
The concept of "data controller" – the organisation responsible for deciding how the information collected online will be used – is a central tenet of both DPR and GDPR. The controller has more responsibilities than the data processor, who cannot change the purpose or use of the particular dataset. It is the controller, not the processor, who would be held accountable for any GDPR sins.
In its response to the ruling, Facebook decided to pretend that the "Like" button was just an average website plugin: "We welcome the clarity that today's decision brings to both websites and providers of plugins and similar tools," Jack Gilbert, Associate General Counsel at Facebook, said in a statement.
"We are carefully reviewing the court's decision and will work closely with our partners to ensure they can continue to benefit from our social plugins and other business tools in full compliance with the law."
Nothing Facebook does seems to hurt its sales: the company has just reported second quarter results, growing its revenue 28 per cent year-on-year to reach $16.6bn. ®