Can we get some EXAMPLES in here that are shitposts outside of off topic.
My general thoughts right now are like this: If we are going with stronger moderation then basically we don't want posts that derail or devalue on-topic threads.
Posting a reaction gif or something like that in a serious thread is totally fine if it's vaguely related and not generally offensive; but doing it all the time, or posting some unrelated meme just to bump the thread or get a reaction out of people is not fine; and various people posting strings of reaction gifs which end up devolving the thread is also not good.
It's ok to sometimes jokingly shit-talk people when they are in on the joke, but it's not ok to make an obnoxious habit out of it, or hijack threads with pointless tangents, or antagonize people to get a rise out of them, post harmful rumors about them, etc.
It's ok to post a short reply to a thread if it has something to do with it, but not to litter various threads with meaningless replies to get your post count up or whatever.
In general if a post is made specifically to get some kind of reaction out of people unrelated to the content of the thread, it's probably not wanted in on-topic boards.
Although it does seem tricky to define what shitposting is, I think it's probably pretty obvious most of the time when you see it. The mods aren't going to be Nazis about it. If people don't try to push the boundaries of reasonable internet conversation in on-topic boards, they should be fine (yes I know much of the community is very young, but we have a meme board now if you just can't control it).
These are just my initial thoughts on stronger moderation, but I'm totally open to other interpretations and suggestions.