So-called patent trolls, companies that buy up patents but use them to get money out of other companies instead of actually making anything with them, are a big thorn in the side of many tech companies. And Google has a new tactic for fighting them: buying the patents first.

On Monday the tech giant announced its "Patent Purchase Promotion" -- an experimental market where Google hopes to get patent holders to name a price for intellectual property they're willing to sell. From May 8 to May 22 there will be a portal where patent holders can submit their information; the company will then review all the submissions and let people know by June 26 if Google is interested in making a deal.

The tech giant is pitching the program as a way to head off the trolls. "Unfortunately, the usual patent marketplace can sometimes be challenging, especially for smaller participants who sometimes end up working with patent trolls," Google deputy general counsel for patents Allen Lo said in a blog post announcing the plan. "Then bad things happen, like lawsuits, lots of wasted effort, and generally bad karma. Rarely does this provide any meaningful benefit to the original patent owner."

The patent troll problem has been getting worse in recent years: A PricewaterhouseCoopers study from last year estimated that patent trolls are responsible for 67 percent of all patent lawsuits filed -- up from 28 percent five years before.

But some are already questioning Google's motives.

"This doesn’t sound like an effort to defeat patent trolls — it sounds like an effort to compete with them," wrote Annalee Newitz, the editor-in-chief at Gizmodo, pointing to a section of an FAQ posted by Google about the program.

"Google maintains a large patent portfolio," the FAQ reads. "Any patents purchased by Google through this program will join our portfolio and can be used by Google in all the normal ways that patents can be used (e.g., we can license them to others, etc.)."

For many years, Google was embroiled in a sort of "patent war" related to the smartphone market with other big tech companies. The company's 2012 purchase of Motorola was thought to be largely driven by a desire to secure patents to support its Android mobile operating system. Google later sold off the headset manufacturer to Lenovo, but kept the bulk of its patents.