I think the way federation currently works spells doom for the fediverse, should any service of it get major traction. Currently, if you subscribe to a community on Lemmy or follow a user on Mastodon, your instance will pull the content of that instance/user and make it available for all to see and interact with. What seems like a good idea to spread content however is becomming the achilles heel of the fediverse: The admins of Lemmy/Mastodon instances are liable in many juristictions for the content their servers are distributing. This means in practice that many Lemmy/Mastodon instances block NSFW content for example, as the admins, understandably so, are either unwilling or incapable of making sure they are not running afoul of any laws.
As such, I think that the fediverse needs to offer a way for users to follow content from other instances without having that content be stored, let alone shared by their home instances.
A question I have at this point is where this criticism is best levied against. Is it the job of Lemmy/Mastodon to provide such a form of federation, or does the ActivityPub protocol needs to be ammended?
Which doesn't work seamlessly. You have to create a new account and re-subscribe.
Lemmy needs to decouple accounts from instances so you have the freedom of movement.