Google is adopting a more rigorous worldwide advertisement policy for content uploaded to YouTube, with aims to clean up its video-sharing site and address growing complaints from advertisers that their messages are being attached to inappropriate videos.

YouTube will impose stricter criteria on the types of videos that can earn advertising revenue through the video-sharing site, and will manually review “top-tier” videos with high view counts and viewer engagement before attaching ads to them, Google executives wrote in a blog post this week.

YouTube’s latest policy tightening comes after the video-sharing site has faced criticism for incidents where ads were placed on violent, racist or otherwise inappropriate videos, prompting major advertisers to leave the platform.

“We’re making changes to address the issues that affected our community in 2017 so we can prevent bad actors from harming the inspiring and original creators around the world who make their living on YouTube,” Neal Mohan, YouTube’s chief product officer wrote on YouTube’s Creator Blog.

“A big part of that effort will be strengthening our requirements for monetization so spammers, impersonators, and other bad actors can’t hurt our ecosystem or take advantage of you, while continuing to reward those who make our platform great.”

Google plans to strengthen the selection criteria for the YouTube Partner Program, which lets creators monetize their videos by attaching ads to them. Google is now imposing stricter criteria over which video channels are accepted into this program.

Previously, channels had to reach 10,000 total views to be eligible for the YouTube Partner Program. But now, channels will have to have 1,000 subscribers and 4,000 hours of watch time within the past 12 months to be eligible for ads.

The new requirements for existing channels will take effect from Feb. 20, Google said. It also pledged to closely take into account factors like community strikes, spam and abuse flags to remove inappropriate accounts and channels from YouTube.

In addition, YouTube said its content management staff will manually screen all videos included in Google Preferred -- a premium service that grants advertisers access to YouTube’s top-viewed content. Ads will only run on Google Preferred videos verified to be compliant with YouTube’s ad criteria.

According to the US tech giant, manual review of Google Preferred channels and videos will be completed by mid-February in the US, and by the end of March in all other markets whether it is available, including South Korea.

Google Preferred videos comprise around five percent of all videos that are uploaded on YouTube globally, according to Google.

By Sohn Ji-young (jys@heraldcorp.com)