Blizzard is in the process of suing Valve over the trademarking of the name “DOTA." As many of you probably know, Valve is currently developing a fully-fledged sequel to the original WarCraft III mod — a mod they didn't originally create, mind you — and is attempting to officially claim the name for themselves through the US Patent and Trademark offices, much to the dissatisfaction of Blizzard, who sees the term DOTA as theirs by extension. The matter will now be settled in court, where Blizzard and Valve will each make the case for why they deserve to be the trademark holder of the name DOTA.
As Blizzard sees it, while they didn't create the free Defense of the Ancients mod for WarCraft III, it has become synonymous to a product they did create. DOTA would not exist if it wasn't for the foundation Blizzard built with WarCraft III. If the roles were reversed, it would be like Blizzard seeing the success of the original Counter-Strike, a fan-made mod for Valve's Half-Life, and developing a Counter-Strike 2 without the consent of Valve, making money off a property that wasn't theirs to begin with.
In legal mumbo-jumbo, here's how Blizzard is expressing their frustration in the matter:
"In contrast to Blizzard, Applicant Valve Corporation ("Valve") has never used the mark DOTA in connection with any product or service that currently is available to the public. By attempting to register the mark DOTA, Valve seeks to appropriate the more than seven years of goodwill that Blizzard has developed in the mark DOTA and in its Warcraft III computer game and take for itself a name that has come to signify the product of years of time and energy expended by Blizzard and by fans of Warcraft III. Valve has no right to the registration it seeks. If such registration is issued, it not only will damage Blizzard, but also the legions of Blizzard fans that have worked for years with Blizzard and its products, including by causing consumers to falsely believe that Valve's products are affiliated, sponsored or endorsed by Blizzard and are related or connected to Warcraft III."
Stepping outside my personal opinions on both development companies, I think Blizzard has a strong case, unless I'm completely missing something in the fine print of this lawsuit. The original DOTA was a free mod for WarCraft III and now Valve is developing a sequel to pass the IP off as their own. That seems fishy.
Either way, the courts will soon decide who gets the rights to the name. The last shot fired was in November of last year when Blizzard followed up their original filing, stating they "respectfully request that this Opposition be granted."