Leading poker site PokerStars has taken legal action against a datamining company in efforts to protect its intellectual property rights, sending a cease and desist letter that has since been obeyed.

Poker Stars is fighting back against data-mining companies, which it says violate its terms and conditions and constitute an infringement on the poker site’s intellectual property rights. In this battle, Poker Stars has most recently set its sights on Poker Table Rankings, a service that tracks literally millions of online poker hands each day, recording data for every game style and limit possible. It then reveals these stats, by player, to its member-clients, giving those players valuable information on their opponents.

Despite Poker Stars’ explicit prohibition of this practice in its terms of service, Poker Table Rankings has still managed to stay afloat, and even more than that, they’ve been able to add a bevy of big poker rooms to its database of sites it tracks, including the poker sites in the Mere Network as well as 888 Poker and Party Poker.

Efforts to thwart PTR have proven difficult and ineffective. So recently, PokerStars stepped up its action into the legal arena.

In an public statement on April 18, 2012, Lee Jones, the Head of Home Games at Poker Stars, said that the site sent out Cease & Desist letters to Poker Table Rankings.

One day later, on April 19, Poker Table Rankings honored the Cease & Desist request under the threat of legal action, stopping the tracking of all hands at Poker Stars.