When you're listening to your favorite podcast — This American Life, maybe, or Radiolab — patents are probably the last thing on your mind. But behind the scenes, the podcasting world has been living in fear of one particular patent that threatens to force many independent producers out of business.

Now, a government board has revoked key parts of that patent, handing a huge victory to podcasters.

The decision makes it a lot harder for producers to be hit with aggressive infringement lawsuits. The company that owns the patent in question, Personal Audio, says it invented podcasting. In 2013, it began going around to podcast-makers, threatening to take them to court unless they paid a licensing fee. Among those affected? TV personality and comedian Adam Carolla, who ultimately settled with Personal Audio but not before spending more than $650,000 defending himself.

"We’re glad the Patent Office recognized what we all knew: ‘podcasting’ had been around for many years and this company does not own it," said Daniel Nazer, an attorney for the Electronic Frontier Foundation, which called for the patent's invalidation.

If you've heard about this case or others like it, then you're familiar with patent trolls. They are companies that own patents but don't really use them to make anything, except lawsuits. Pretty much everyone agrees they're a horrible drain on innovation and the economy; the Federal Trade Commission gave a slap on the wrist to one last year, and Congress is currently debating how to reduce their impact.

Friday's ruling by the U.S. Patent and Trademark Office invalidates five provisions of Personal Audio's podcasting patent. Specifically, it takes aim at claims 31 to 35, which describe an "apparatus for disseminating a series of episodes represented by media files via the Internet as said episodes become available."

The PTO's decision finds that claims 31-35 fail a basic test that all patents must satisfy concerning the "obviousness" of the claimed invention.

You may be wondering why the patent office is siding against a patent it already granted. If it was already approved, then wouldn't it have already satisfied the obviousness test at one point or another?

Well, the PTO's ruling highlights the importance of something called inter partes review, which basically allows people to ask for a patent to be invalidated after the fact. There are a number of other ways to challenge bad patents, such as going to a federal court, but it turns out that inter partes review is actually more effective at getting patents overturned.

"In district court, patents go down 45 percent of the time — in IPR, it's closer to 80 percent," Hans Sauer, deputy general counsel for the Biotechnology Industry Organization, told a Senate panel last month.

The IPR has become an increasingly significant weapon in the fight against trolls, but Congress is currently considering other ways to address the issue. House lawmakers have re-introduced the Innovation Act, a bill that would impose new requirements on patent holders and shift incentives to deter them from filing frivolous lawsuits.

Friday's decision from the PTO is likely to add momentum to the push for patent legislation. On Tuesday, the House Judiciary Committee is expected to hold a hearing to discuss the Innovation Act.

A spokesperson for Personal Audio didn't immediately respond to a request for comment.