The UK's new online safety rules, explained:
Around 6,000 porn sites start checking ages in UK

Chris Sherwood, chief executive of children's charity the NSPCC, said Friday's new rules mean services "can no longer evade their duty for protecting children".
He added it was "high time for tech companies to step up" and prevent children encountering harmful content on their platforms.
"Children, and their parents, must not solely bear the responsibility of keeping themselves safe online," he said.
For Prof Elena Martellozzo, professor of child sexual exploitation and abuse research at the University of Edinburgh, the rules send a message to the tech industry that "child safety and child protection are not optional".
"Failing to act is no longer excusable under the guise of technical complexity or business models," she added.
Not all believe Ofcom's rules go far enough to protect children as intended, however.
The Molly Rose Foundation, a charity founded by the family of Molly Russell - who took her own life at the age of 14 after seeing harmful content online - has said stronger legislation is needed to better protect children.
Andy Burrows, the charity's chief executive, said Ofcom has prioritised "the business needs of big tech over children's safety", with thresholds for requirements and estimated costs for changes falling short of what is needed to force the largest companies to take action.
Derek Ray-Hill, interim head of the Internet Watch Foundation, meanwhile welcomed the new rules for sites allowing porn but said "there is still more to be done".
He said platform operators should be considering how to make them safer by design and "doing everything they can to make sure we are building an internet that is safe for everyone".
Others have have expressed concern that people may seek ways to circumvent so-called age gates on porn sites - potentially pushing them towards less regulated spaces with more dangerous and explicit sexual material.
"A lot of the porn out there is incredibly derogative to women and there's a lot of violence and aggression," said Reed Amber Thomas-Litman, a sex worker and educator.
"Of course people, not just kids or young adults, are going to mimic that."
She told Newsbeat providing information about porn as part of the sex education curriculum could "help young adults understand it is a fantasy, it is not reality".
Age checks could also negatively impact people who do not feel comfortable sharing their identity, such as LGBTQ+ people, she said.
"If you have to hand over your ID, that means you have no protection where that information is going," she said.
"It could go to third party companies and who knows what they'll do with that information."
Many of the sites which operate age verification services say they do not retain ID, videos or images required for them to carry out age checks for any longer than necessary.
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