TLDR: Subreddits are protesting against Reddit's API changes, and r/pics, a subreddit with over 30 million members, has marked itself as NSFW (not safe for work). This means that advertisements can no longer be displayed alongside posts in the subreddit. The protest started in June when thousands of subreddits participated in a blackout to protest Reddit's plans to charge for API access. The changes have resulted in third-party apps like Apollo shutting down. As part of the protest, r/pics initially only allowed images of comedian John Oliver to be shared and later amended its rules to allow media featuring Oliver, including erotic fan fiction. The subreddit's moderators posted an "open letter" reminding the community not to swear, as marking the community as NSFW would deprive Reddit of advertising revenue. Reddit has reportedly removed mods for marking their communities NSFW as a protest. Despite this, r/pics was officially marked NSFW on Monday. Other subreddits, such as r/videos and r/funny, are also protesting in their own ways.