You do not need age verification in the vast majority of cases.
Moderation is part and parcel of running forums and all platforms and software provide tools for this, it's nothing new. If someone is not prepared to read submissions or to react quickly when one is flagged then perhaps running a forum is too much of a commitment for them but I would not blame the law.
In fact I believe that forum operators in the UK already got in legal trouble in the past, long before the Online Safety Act, because they ignored flagging reports.
Right, so 24 hour coverage is already too expensive for most forums and your position is that small forums should not exist.
Small forums should and can exist. They are not required to have 24 hour coverage.
You said above "If someone is not prepared to read submissions or to react quickly when one is flagged".
Does the Act specify "quickly"? Does several hours count as "quickly"?
Not the OP but I don’t recall the actual law saying 24/7 moderation was required.
Given the UK already has a “watershed” time where terrestrial TV can broadcast mature content between set hours (from 9pm), I cannot see why the same expectation shouldn’t exist that moderation isn’t happening outside of reasonable hours.
Typically with laws in the UK (and EU too) is to use more generalised language to allow the law a little more flexibility to apply correctly for more nuanced circumstances. Such as what is practical for a small forum to achieve when its specialty isn’t anything to do with adult content.
You’ll definitely find examples where such laws are abused from time to time. But they’re uncommon enough that they make national news and create an uproar. Thus the case goes nowhere due to the political embarrassment that department draws to itself.
Though to be clear, I’m not defending this particular law. It’s stupid and shouldn’t exist.
Reacting quickly means what's proportionate and reasonable. This is quite standard wording for a law.
The Act (section 10 about illegal content) says that "In determining what is proportionate for the purposes of this section, the following factors, in particular, are relevant—
(a) all the findings of the most recent illegal content risk assessment
(b) the size and capacity of the provider of a service."
"24 hour coverage" is the maximum that can be achieved so it's not going to be proportionate in many, if not most, cases. People have to ask themselves if it is proportionate for a one-man gardening forum to react within 5 minutes at 3am, and the answer is not going to be "yes".
Obviously you can also automatically hide a flagged submission until it is reviewed or have keywords-based checks, etc. I believe these are a common functionalities and they will likely develop more (and yes, a consequence might be to push more people towards big platforms).
People need to have a calm analysis, not hysteria or politically-induced obtuseness whatever one might think of this Act. If they are a small and not in the UK they can probably completely ignore in any case.