I was wondering, did I miss the federated authentication service? When a user has a mastadon account on one of the federated services, it is possible to follow and post on mastodon, react on lemmy and follow lemmy users, but creating a lemmy post isn’t possible. When a user has a lemmy account, interaction with mastodon is possible, but to follow you need a mastodon account.
Isn’t there an authentication service, so you can create [email protected] and interact wuth all services?
No, there is no centralised account service for the Fediverse, the accounts are owned by the individual websites (so in your case, lemmy.ml). The different softwares can then interact over the ActivityPub protocol, but how this works depends on the two softwares and what is currently implemented.
Lemmy currently cannot interact with Mastodon directly, but Lemmy communities and users will show up on Mastodon for people to follow and interact with. Lemmy users can interact with posts and comments that Mastodon users post on Lemmy though.