What just happened? In January a report was released that showed the extent to which the four main wireless carriers in the U.S. shared and sold customers' data, including live location information. Now the big four are facing a class action suit seeking damages in a landmark case for privacy rights.

At the start of the year we reported on a Motherboard investigation into the data selling practices of the big four U.S. wireless carriers: Verizon, T-Mobile, Sprint and AT&T. The investigation revealed that each company sold to third parties confidential information including real-time location data. This data was purchased by middle-men before being bought and used by law enforcement to track phones without a warrant, and even bounty hunters.

In one test case, Motherboard paid $300 to successfully discover and track the location of a subscriber.

Each company 'vowed' that they were either ending such practices imminently or that they would do so in the coming months. But as far as their customers are concerned, such promises don't go far enough, and the damage has already been done.

So now come the lawsuits. Each case is being put forward in the name of at least one subscriber but is being made on behalf of millions of customers. An estimated subscriber count for the period April 30, 2015 to February 15, 2019 means that in total 300 million subscribers are being represented; 100 million each for Verizon and AT&T, and 50 million each for T-Mobile and Sprint.

The suits will ultimately come down to whether or not the firms violated section 222 of the Federal Communications Act (FCA), which obliges companies to protect confidential information from unauthorized third parties.

No doubt each carrier will hide behind generic privacy statements to say they were allowed to engage in data selling, so it will be interesting to see just how far the courts are willing to take things, in particular the definition of 'unauthorized'.