Big tech companies are under fire, as conservatives are alleging censorship on social media platforms like Facebook and Twitter.

Twitter co-founder and CEO Jack Dorsey said that the social media giant does not ban users for their political viewpoints – only for violating its rules, while admitting that the bias of the platform’s staffers is “more left leaning.”

And Facebook recently apologized for removing content of conservative educational site Prager University (PragerU) and pro-Trump social media stars Diamond & Silk. But it's not just those platforms that are being accused of targeting conservatives.

Author and presidential historian Doug Wead says he's being "shadow-banned" by YouTube and its parent organization, Google, and that the visibility of his videos has been restricted in search results.

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"If you type the name of your video into YouTube and it doesn't come up, you know you've been shadow-banned. That's the whole purpose of a search engine, is to find what you're looking for," Wead said on "Fox & Friends."

He revealed that he bought an ad to promote a video of his June 2017 appearance on Fox Business Network, but the ad was blocked and Google informed his team it was because the video contained hate speech.

When he tried to re-submit the ad, it was again blocked and his Google account was suspended.

He said he called Google and was told that it was blocked not because of what was said in the video, but because of a crawler at the bottom of the screen, which quoted President Trump calling Robert Mueller's investigation a "witch hunt."

Wead highlighted that YouTube enlisted "trusted flaggers" to delete questionable video content from its platform. Among the "trusted flaggers" is the Southern Poverty Law Center, a controversial left-leaning nonprofit known for its classification of hate groups and extremist organizations.

"That's when I could see clearly in their own metrics that some videos were being shadow-banned and others weren't," Wead said.

He pointed out that he appeared on "Fox & Friends" in March 2017 to discuss his book about Hillary Clinton's election loss, and the video went viral. After the "trusted flaggers" were put in place, however, the video views immediately plummeted and have stayed there ever since.

"They hide your videos so nobody can find it."

Watch more above.

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