The websites impacted by the UK's new "porn block" law include free video hosting sites such as PornHub and RedTube, as well as commercial providers of online pornographic content. If they fail to implement the age verification technology, they face being blocked for UK users. MindGeek, the company that owns PornHub, YouPorn, RedTube and Brazzers, is working on an "AgeID" system that directs users to a non-pornographic page to verify their age using a driver's license or passport.

The UK is distinct in being the first in the world to implement such a law. British officials pushed for a porn block following concerns over kids accessing sexual material on the internet. "Adult content is currently far too easy for children to access online. The introduction of mandatory age-verification is a world-first, and we've taken the time to balance privacy concerns with the need to protect children from inappropriate content," said UK Digital Minister Margot James in a press release.

The controversial porn block was originally supposed to go into effect on April 2018, but was pushed back by the government a few times. Critics of the porn block law argue that the law would essentially create a database of UK porn users, which would pose a huge problem if it were to ever leak.

Notably, the UK's Department for Digital, Culture, Media and Sport sent Wednesday's press release on the porn block law in an email that exposed the email addresses of over 300 journalists, The Guardian reported. "Data leaks could be disastrous. And they will be the government's own fault," said Jim Killock of the Open Rights Group.