Doesn't help. Everything from the meme/joke/fun communities you'd expect people to use to tune out The Horrors™ to discussion about the ActivityPub standards (what little exists that doesn't conflate it with Just Lemmy or Just Mastodon) devolve to US politics in like two comments. For me at least this entire section of fedi is a US politics-radioactive one I try spending as little time as possible (that includes posting non-politics!)
I find myself having significantly more fun on the microblogging side of the fedi, ruining jokes to ground in like 4 minutes with my oomfs and making followup meta jokes about how jokes only last 4 minutes. People actually use content warnings to hide away The Horrors™ when they want to talk about it, which means filters actually work. (Things like alt text for images also helps with word filters!)
Mastodon moves also take your following with you. You'll still have to reimport followers, but you don't lose your ""audience"".
There are software out there (Sharkey for microblogging (Firefish also had it but theirs was broken and leaked DMs), PixelFed for images from Instagram specifically) that allow some form of post imports, but these are only brand new posts that happen to have the same content as the old ones, and not "replacing the author of a post".
There are work going on regarding nomadic identity and more seamless account migrations across instances, but hell will freeze over before any of the mainstream fedi software implement anything close to that, mainly due to how significant of a conceptual change that is.
Mastodon's WIP implementation uses the conventions of Smithereen semi-standardized as FEP-400e. It's not something "incompatible with any other platform" (it's not commonly implemented, but it's not bespoke for no reason either). FEP-1b12 used by Lemmy also has it's own quirks (why are we Announceing activities?) and the specific implementation used by Lemmy will likely not interoperate far without breaking changes that will upset one or the other party, mainly the fact that users and communities can use the same webfinger handle.
Either every single other software needs to have specific quirks for Lemmy in order to handle this as most (reasonably) assume the username@domain combo will be globally unique, or Lemmy instances need to go on an account or community deletion spree to make this non-unique. You can easily DoS a user or community's federation outside the threadiverse bubble by setting up one of the other with the same username on the same instance.
PS: Lemmy is the only platform that has had an exploit that overshadows Mastodon’s success
what? I'd like to remind you Lemmy is the third most largest open AP server software. After Mastodon, and Misskey. (by a not insignificant margin, with Misskey having 8.6% of all known users by FediDB, and Lemmy having 3.8%) Just because they're Japanese doesn't make them any less a part of the network, and they do have their own innovations (MFM, and emoji reactions are just the ones that federate. They also had quotes before many others but I think they're not the first on that one).
There's no real reason to. Your own instance (in this case, lemmy.world) has the real view of the thread by the virtue of being the instance starting the thread. lemmy.ml only has it's own copy of this thread that's likely reasonably accurate (compared to any other random instance out there, considering it hosts the community), but it's not the original version, which is what the fediverse link points to.
Which instances did you try? I want to check if it was the background radiation of USpol inherent to most online communities you're sick of (which there really isn't a solution beyond keeping up with the newest buzzwords to add to your filters for from what I can tell) or the dot-social/kolektiva/twitter-like "my political happenings are too important for a content warning and must be boosted to everyone's eyes 24/7" variety of USpol (which there is a ton of in Lemmy as well but i don't think most people are ready for that debate yet)
The second one can be ameliorated a little by picking a smaller, sillier instance (hint: the weirder the domain, the better) and not following The Same Large Accounts Everyone Does.
In fact, I would advise against Mastodon the software altogether and instead point you towards instances of Akkoma or one of the not-Japanese Misskey forks such as Sharkey, Firefish, or Iceshrimp. The vibes of most instances I've seen seem to be cozier, and the Bubble timeline (called Recommended Timeline by some software) helps with discovering people to follow beyond the said Large Accounts.
The Pleroma family of ActivityPub servers are on Elixir and their bottleneck seems to be their awful database schema where everything is JSONB, and even then they're known to be quite lightweight, so I assume with a proper DB schema it'd work quite well...
After seeing a team of fedi software developers drop their Matrix bridge to their Discord after the total lack of moderation tooling resulted in an extremely transphobic spam wave, I for one am not surprised.
Another team I'm aware of also dropped Matrix for other reasons, but went for Zulip instead, which is also open, but more collaboration oriented a la Slack rather than community oriented like Discord, which probably would not fit what the group in the OP is looking for.
Lemmy's cross posts are separate posts that just happen to link to the same thing. so only replies to the original post would be sent with the current design.
that said, i severely doubt Lemmy will gain anything from this. publishers will not be sending out their posts to any communities, and i highly doubt they will expose any fep-1b12 group actors you can subscribe as a community.
kbin/mbin with it's ability to follow users may work better, assuming people test their federation with software other than mastodon, and accept any of the interoperability bugs as actual bugs instead of ignoring them. (lemmy itself is no stranger to this: the fact that users and communities can share the same username break quite a bit)
while i don't have any specific opinions about this that other people haven't addressed, i just want to flag up something;
How this could be enforced? No voting from the All and/or Local feed. Seems easy and straight forward.
this seems unenforcable. as in, you can't really tell where someone discovered a post from. yeah you can just remove the buttons from those views clientside and it'll probably work for the majority of cases, but alternate clients or modifications to lemmy-ui can simply put the buttons back in (or in cases of unmaintained or differently opinionated clients, just not remove the buttons at all). the backend can't really differentiate which view a vote comes from. federation especially can't differentiate which view a vote comes from.
![kopper [they/them]](https://lemmy.blahaj.zone/pictrs/image/PG5vaKqMsg.webp?format=webp&thumbnail=128)
Doesn't help. Everything from the meme/joke/fun communities you'd expect people to use to tune out The Horrors™ to discussion about the ActivityPub standards (what little exists that doesn't conflate it with Just Lemmy or Just Mastodon) devolve to US politics in like two comments. For me at least this entire section of fedi is a US politics-radioactive one I try spending as little time as possible (that includes posting non-politics!)
I find myself having significantly more fun on the microblogging side of the fedi, ruining jokes to ground in like 4 minutes with my oomfs and making followup meta jokes about how jokes only last 4 minutes. People actually use content warnings to hide away The Horrors™ when they want to talk about it, which means filters actually work. (Things like alt text for images also helps with word filters!)