A change to US law means patent and trademark officials must allow the public to report that a patent claim is bogus because the technology is already in use. That’s led to the creation of a dedicated website for making such reports.

The change comes in the America Invents Act, which became law last year. The clause in question took effect from September 16 this year and states that “Any person at any time may cite to the Office in writing prior art consisting of patents or printed publications which that person believes to have a bearing on the patentability of any claim of a particular patent…”

Prior art means the process put forward for patent can be shown to have already been used anywhere in the world. If accepted, prior art will usually kill a patent application.

The legal change is significant because patent examiners have only a limited time (around 20 hours) to review each application, making it difficult if not impossible to look in every place an “invention” might have been used before.

The US Patent and Trademark Office has now asked for the help of Stack Exchange. That’s a company that runs dozens of question and answer sites where users can vote for how useful submitted answers are to give them added prominence: think Yahoo! Answers without the dribbling idiots.

Stack Exchange is working alongside the USPTO and Google Patent Search to produce Ask Patents, a searchable database with tags for keywords, classification and patent number. Once somebody submits an example of prior art, readers can vote on whether they think it is indeed a match. Patent officials can then concentrate on the submissions that appear most credible evidence of prior art.

According to Stack Exchange:

Collectively, we’re building a crowd-sourced worldwide detective agency to track down and obliterate bogus patent applications. Over time, we hope that the Patent Stack Exchange will mitigate the problems caused by rampant patent trolling. It’s not a complete fix, but it’s a good start.