In the past there were bots spreading ads for pills and stuff, but now most instances ask to tell a bit about yourself before registering and don’t federate with instances that don’t. That eliminated practically all of it as far as I’m aware. However sometimes there are accounts like these:

that go around spamming content that intentionally seems to aim to disturb users. Not sure if they are bots or humans, but they are banned relatively quickly.

Regarding the karma-farming bot accounts commonplace on Reddit, I think there’s no incentive for the creation of such bots, since most Lemmy instances do not have a total user point/karma count like on Reddit.

I don’t think so. Probably still too small

The majority of new accounts created at mander.xyz would post ads about pills or crypto wallet scams shortly after being created. Now I have to manually accept registrations, and many do write that they want to make a post about their product. I deny those. But a few do get through.

I am not sure that they are bots, though, because they do fill in the registration form. And I might be wrong, but I think that a bot would need to be tuned specifically to interact with lemmy instances. I think that these might be actual people that manually crawl the web and spam.