Is rule 21 actually enforced? Very few people follow it, and the couple of times I have reported it, nothing seemed to be done. Is it worth reporting at all?
Yes it is. I always report them and they're handled eventually and I handle the ones I can (made by newbies), but I think there's a lack of Global Moderators and Marketplace mods that can handle them, not to mention they're probably not a top priority and deleting posts, especially many, takes longer than dealing with other reports etc.