This is what I do.
Change the setting "Registered users" usergroup for "Follow Forum Moderation Rules" to No.
Create a new usergroup called "Verified users" based on the settings for Registered users, but change the moderation rules setting to Yes.
Set up a promotion so after one post (or however many you want) registered users get moved to the verified users group.
Using this method users do not get to post openly until they have had at least one post approved. It means you still have to wade through spam yourself, but your users shouldn't see it.
Hope this helps.
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What I also found was useful with this method is something that makes posts pending moderation more obvious to mods and admins. The following modification is great for this:
https://vborg.vbsupport.ru/showthrea...t=notification