User to user websites & sites where pornography is uploaded are now making preparations in order to ensure that they do not fall foul of the forthcoming age verification requirement.
These include verifying users themselves or outsourcing the function, blocking the UK from their service, closing down etc.
Although this is not endorsed by Ofcom (the regulator for these sites), this site does contain some useful information for those affected by this change:
OnlineSafetyAct.co.uk