This is not going to be a blogpost about “Why do people still use Reddit instead of everyone moving to Lemmy?”. I noticed that even with Mastodon users, who already understand and like the advantages of decentralized platforms, the usage of Lemmy is extremely small, and more people use Reddit. Most of them haven’t even heard of Lemmy. To be fair, the Reddit usage also seems to be fairly low.
activitypub is a protocol. like email.
instances are just what provider you want to use, gmail, hotmail, outlook, etc.
and the ‘platform’ lemmy, piefed, mastroton, pixelfed, is just the aesthetics
Unlike like email the fediverse servers defederating / blocking each other more.
dogmail can send to birdmail but not to catmail.
Google does a lot of “defederating” (for lack of a better term), it’s one of the reasons why setting up and hosting your own email is one of the nightmare sections of selfhosting communities.