Oath-owned social blogging platform Tumblr has announced an update to its terms of service that bans adult content from being hosted on the site. The change comes following concerns over the number of pornography-focused blogs on the platform, which recently saw the app removed from Apples iOS App Store. However, users of the service have criticised the approach taken in flagging content for removal, which relies heavily on AI-powered bots to identify adult content.

While the ban on adult content will not come into place until 17 December, Tumblrs algorithms are already flagging content that will be outlawed under the new rules, and notifying users who have posted it. Posts with pornographic content will be set to private, which will prevent them from being shared elsewhere on the platform.

The new guidelines ban photos, videos and GIFs of human genitalia, female-presenting nipples and any media involving sex acts, including illustrations. Exceptions exist for nude classical statues, political protests featuring nudity and breastfeeding, and text is exempt, so erotica is still permitted.

While Tumblrs userbase has vocally called for a solution to the prevelence of porn blogs on the platform that spam content or are run by bots, the new guidelines have been met with outcry, especially regarding the way they have been executed. A wide variety of posts containing no explicit or adult material have been flagged by the algorithm, while the inclusion of illustrations in the guidelines has worried Tumblrs active artistic communities.

“There are no shortage of sites on the internet that feature adult content,” said Jeff DOnofrio, chief executive of Tumblr. “We will leave ti to them and focus our efforts on creating the most welcoming environment possible for our community.”

According to Tumblr, users will have a chance to appeal decisions in situations where they think there has been a mistake, and staff have admitted that theres a chance the automated tools could make errors. Currently, users who have been notified that their posts contain adult material have to go to each individual post to appeal the decision, and the process only works on the web or Android version of the app.

Tumblr has been known for several years for its relatively hands-off approach to adult content and sexual images, and several sex-focused subcultures have flourished on the platform, including those making and sharing explicit fan fiction and art, and LGBT erotica and pornography.

The change in Tumblrs rules appears to have been triggered by an incident a few weeks ago, when Apple banned the iOS version of the app from its App Store after child pornography was found on the platform. While no-one is defending the presence of child pornography on the platform, some are criticism Tumblr for its scattershot approach to adult content.

“With its massive distribution and strict rules, Apples App Store has had a broad homogenizing and sanitizing effect on the internet,” wrote Jason Koebler and Samantha Cole at Motherboard. “There are fewer and fewer mainstream sites and services that support porn and adult content, and much of that attitude has grown out of Apples strict controls over the App Store and the iOS ecosystem.”

Others have pointed to the recently passed Stop Enabling Sex Traffickers Act (SESTA), which has changed US federal laws to make websites responsible for any prostitution and sex trafficking that is facilitated via their platform. While the law was intended to better police sex trafficking, sex workers have criticised it for eliminating safe venues on which they could advertise their services. The personals section of Craigslist, certain groups within Reddit and a number of websites have already been shut down as a result of SESTA.