We just need to be better about simplifying the explanation. Don’t tell people “it’s a federated website using an activitypub backend to communicate like mastodon, but only links to federated lemmys not including mastodon instances…” Tell them “it’s a fourm that shares posts and comments with other fourms that agree to work together”. If they want more detail they can easily find it themselves.
Federation is the invisible glue that makes it all work… I have my own server but i can talk to you on lemmy.world without having to think about it or do anything special. Most people joining in the future won’t need to care federation even exists, just like they don’t care SMTP exists.
That said I suspect there will be a few mega servers anyway… just like gmail… people seem to like being where everyone else is.
I feel like the explanation using email as an example works pretty well. Most people understand how different emails from different providers can communicate, but their account is hosted on one platform.