There is a substantial amount of spam and NSFW posts on the All page coming through already. Most NSFW posts aren’t being tagged as such and are coming right through. I am not sure how this can be weathered but we need something in place fairly soon, I feel like we are days away from rivers of bad stuff, especially via some of the federated instances.
EDIT: I personally don’t care much about the NSFW aspect, more in the lines of what a newcomer will be seeing when they get to the main page. 99% of the newcomers don’t know / care about federation and have no idea how to turn that off. Liability for the server owner is also an element of consideration.
Bizarrely I think this is an example of the success of the services as they grow. Increase in use reveals problems that people didn’t realise were there, which allows them to be fixed.
In this case, NSFW tags not being applied manually. As others have pointed out, NSFW tags might be better applied globally depending on either the hosting service &/or community.
It’s a test of the fediverse which I have no doubt will be resolved.
You already can mark entire subs as NSFW. I think the problem is that a bunch of folks created subs that weren’t marked as such.
Though with federation, it’s always hard to say just what features other people have. I only personally verified that kbin lets you mark subs as NSFW, but someone told me Lemmy does, too.