Doesn't seem to be a big bot problem at this time. Then again, given the shitshow both of us just left, we'd be hard pressed to see it after the pot we'd been boiling in (like frogs)..
The sites are federated - which means the various lemmy instances are hosted by different people and the main one - lemmy.world - had admins that give out updates and say how they're working on this, that and the other and trying to deal with scrapers..
I signed up through lemmy.zip as that instance hosts more tech-heavy content and it's smaller than .world.
I think the entre fediverse is still small enough that the mods can deal with the bots easily enough.
There is one instance, lemmy.ml, that is apparently run by "tankies" who are pro-Russian Putin supporters. Ehhhh, no. Have read they have a tendency to make bad faith arguments and they ban people - which is sucky, so I decided not to bother with that. There is a post I found that offers instructions on how to ban the instance so I do not get anything from it. Don't need or want the political belligerence, thankyouverymuch!
The whole idea of the federated sites is really cool! I love how it works. Decentralized. There are multiple different servers that operate with the same cross-communication protocols for the messages, so from where I logged in and took a membership on the .zip instance I can sign up for communities on other ones. I have subscribed to communities on multiple instances.. music@beehaw.org is somewhat different than music@lemmy.world..
Start digging through the various instances, you may find the niche communities you're looking for are there, or there's something similar enough that you can start to put up your own posts and make it work.
There's tons of instances - piefed, sh.itjust.works, slrpnk.net, blahaj.zone, beehaw.org, lemmy.ca, feddit, mander.xyz (it's got a cool little star trek comm - totally am in there..) dbzero.com, midwest.social - so they're all different servers that link their content into a web.
I also like lemmy.zip because it DOES have the "old.reddit" style for the layout (of course it would, it's where the techies hang..) and all the comms I've subbed to display in the old format - even if the instance doesn't offer that UI.
Heck yeah!
It's non-profit so there's a donations page - I'm going to be throwing down some $$ because, well.. what beats no ads? It's delightful.