The online community forum tightens restrictions on what can be published on the site and even bans some of its most hateful communities.

Reddit users now have the option of not seeing racist or hateful commentary on the popular online community unless they choose to, thanks to an update to its content policy.

Chief Executive Officer Steve Huffman announced the new policy on the community forum site Wednesday, though he added that the policy would continue to evolve. The policy -- first floated last month -- introduces the concept of "quarantining" content, applying a set of restrictions to a community so that its content is available only to those who opt in.

"We will quarantine communities whose content would be considered extremely offensive to the average Redditor," he said, adding that those communities will generate no revenue for the site.

Reddit also banned a handful of communities "that exist solely to annoy other Redditors, prevent us from improving Reddit, and generally make Reddit worse for everyone else," Huffman said. One of those banned sites was Reddit's notoriously hateful white supremacist community.

With today's move, Reddit joins many of the world's largest social networks, including Facebook and Twitter, in ramping up efforts to police content posted by users. It also sends a message about how Reddit hopes to balance its identity as an open community forum with users' expectations that it be a place for positive interactions and information sharing.

Over the last several months, Reddit has been caught in a maelstrom of controversy over its policies regarding the freewheeling commentary that has made it both wildly popular and a sometime symbol of the Internet's darker side. A number of prominent employees have departed in that time. Huffman is now its third CEO since November.

Founded in 2005, Reddit -- one of the most trafficked sites on the Web, with nearly 164 million visitors per month -- has long seen itself as a community devoted to open and honest discussion. But its traditional anything-goes approach has allowed some of the worst aspects of the Internet to fester on the site, including the growth of forums, or "subreddits," devoted to racist or homophobic notions.

Despite its troubles, controversy, and employee losses, Reddit is flush with cash. Reddit announced in September that it raised $50 million from prominent venture capital firms Andreessen Horowitz and Sequoia Capital. Reddit also announced at the time that it would provide 10 percent of equity in the company to its own community of users "in recognition of the central role the community plays in Reddit's ongoing success."