Microsoft's never-ending war on software piracy caused some collateral damage this week. The victims? A handful of prominent YouTube video bloggers.

The bloggers—including LockerGnome founder Chris Pirillo and FrugalTech host Bruce Naylor—took to Twitter on Tuesday, with the hashtag #Microstopped, to complain that they had received erroneous copyright infringement notices for videos that were often several years old. The notices were filed under the Digital Millennium Copyright Act, the U.S. law that seeks to control access to copyrighted material on the net.

Microsoft apologized for the notices, blaming the issue on wayward comments. "[S]ome of these videos were inadvertently targeted for removal because there were stolen product keys embedded in the comments section of the videos," a Microsoft spokesperson said in statement sent to WIRED, referring to keys that would allow access to Microsoft commercial software. "We have already taken steps to reinstate legitimate video content and are working towards a better solution to targeting stolen IP while respecting legitimate content.”

The situation shows that, 16 years after it went into effect, the DMCA is far from the ideal way to police copyrighted material—mainly because it makes it too easy for big companies like Microsoft to silence the little guys, sometimes for no good reason.

Chris Pirillo at his computer. Joi Ito/ Flickr

Pirillo says he learned—after sending a counter notice to YouTube—that a company called Marketly sent DMCA notice on behalf of Microsoft. Marketly, which was founded by former Microsoft engineer Pulin Thakkar, uses algorithms to spot piracy and counterfeiting on the net. The company's website boasts that it can "generate actionable intelligence from Big Data analysis and machine learning technologies."

According to Google's Transparency Report site, Marketly has requested that Google remove nearly 11 million different URLs from its search engine on behalf of Microsoft since 2011.

This round of complaints over the company's practices began with Naylor and FrugalTech. On Tuesday, Naylor posted a video explaining that YouTube had removed one of his videos after someone filed—on behalf of Microsoft—a DMCA takedown notice. Under the DMCA, web hosts and internet service providers must immediately remove allegedly infringing content when notified by the copyright holder. But Naylor's video, which you can now find on the video sharing site Vimeo, didn't include so much as a screenshot of Microsoft Windows. It was merely a video of Naylor speaking into the camera and explaining why he thought Windows 8 wasn't selling well.

Pirillo says he received his own takedown notice while watching Naylor's video, and soon discovered that other bloggers had received similar notices. That spurred him to create the #Microstopped to find bring attention to Marketly's behavior. We've counted at least eight different bloggers who received notices on Tuesday.

At first, Naylor blamed the removal of his video on the fact that his video was critical of Microsoft. "It really pissed off somebody and they're looking for any excuse to take it down," he said in his video. But many of the videos that have been taken down weren't critical of Microsoft at all. Mark Watson, the host of a tech-focused YouTube channel called SoldierKnowsBest, received a takedown notice for a simple instructional video. "It was a video telling people how to download the Windows 7 Beta from your website in 2009," he tweeted.

Likewise, Pirillo's video was about how to upgrade Windows 7. As he put it: "This isn't about censoring negative reviews so much as it is the gross abuse of YouTube's copyright flagging system and is not without precedent."