“Reddit needs to be a self-sustaining business, and to do that, we can no longer subsidize commercial entities that require large-scale data use,” Steve Huffman, Reddit’s chief executive, said on Friday in an “Ask Me Anything” discussion on the site.

But the charges have set off a major backlash among the volunteer moderators of the site’s diverse communities, who said they would close off access to their groups for at least 48 hours, beginning Monday, in what they called a coordinated protest.

Moderators of some of Reddit’s most popular subreddits — including r/funny, with more than 40 million members, and r/gaming, r/Music and r/science, with more than 30 million members each — were taking part in the protest by setting their pages to private and posting messages denouncing the new terms and pricing.

Moderators of many smaller groups had also gone dark as part of the demonstration.

For a brief period on Monday, the protest made it difficult for some users to access Reddit as “a significant number of subreddits shifting to private caused some expected stability issues,” a Reddit spokesman said, adding that the problems had been resolved.

The developers of several popular apps said they would have to shut them down because of the new pricing system.