https://www.ofcom.org.uk/siteassets/resources/documents/onli...
It amounts to your basic terms of service. It means that you'll need to moderate your forums, and prove that you have a policy for moderation. (basically what all decent forums do anyway) The crucial thing is that you need to record that you've done it, and reassessed it. and prove "you understand the 17 priority areas"
Its similar for what a trustee of a small charity is supposed to do each year for its due diligence.
You just have to make individual value judgements every day on thousands of pieces of content for SEVENTEEN highly specific priority areas.
Then keep detailed records on each value judgement such that it can hold up to legal scrutiny from an activist court official.
> Any competent forum operator is already doing all of thisWhat is your evidence that the record keeping described by the parent is routine among competent forum operators?
https://russ.garrett.co.uk/2024/12/17/online-safety-act-guid... has a more comprehensive translation into more normal English.
You will need to assess the risk of people seeing something from one of those categories (for speciality forms, mostly low), think about algorithms showing it to users (again for forums thats pretty simple) Then have a mechanism to allow people to report offending content.
Taking proportionate steps to stop people posting stuff in the first place (pretty much the same as spam controls, and then banning offenders)
The perhaps harder part is allowing people to complain about take downs, but then adding a subforum for that is almost certainly proportionate[1].
[1] untested law, so not a guarantee