Good points. First of all, it doesn't matter which instance you're on. You can still follow your friends, influencers, etc. on other instances.. unless your instance has the other instance in its blocklist (e.g. if it doesn't adhere to moderation rules that apply on your instance).
Natural re-centralization is an issue, with mastodon.technology and mastodon.social being by far the largest instances. This could devolve to a situation like you have with email / Gmail.
Another challenge is that Mastodon as early adopter of ActivityPub has made a number of required implementation choices to fill in the blanks of the spec. They support a bunch of custom properties in the message format, plus they use the Mastodon client API instead of ActivityPub client-to-server. Their dominance wrt running Mastodon instances means they have a big say in how Fediverse evolves.
Luckily the project team is open-minded, and mostly on the same page to others wrt fediverse innovation.
Thanks for the clarification. I'm not terribly educated on the state of Mastodon/similar federated social media.
Also interesting that you brought up Gmail/email. I've thought for a while (admittedly as someone far more on the "user" side than the "developer" one) about how email is an example of how things might work better. For as much as Gmail and a few others have captured the vast majority of the average userbase for personal email, it's still reasonably easy to choose a different provider (and can even roll your own if you really thought it worthwhile).
Switching email providers doesn't stop me from emailing people who use Hotmail or Gmail (ignoring for a minute any issues of overzealous filtering of uncommon mail servers). The individual services can implement their various extra features like spam blocking, auto sorting, etc. but for the most part, the common protocol means that an email from me@me.server can still be sent to a list of addresses at gmail.com, aol.com, hotmail.com, etc. If I want to send a message to people on Facebook, I need an active "valid" Facebook account that can be tied to their social graph.
Natural re-centralization is an issue, with mastodon.technology and mastodon.social being by far the largest instances. This could devolve to a situation like you have with email / Gmail.
Another challenge is that Mastodon as early adopter of ActivityPub has made a number of required implementation choices to fill in the blanks of the spec. They support a bunch of custom properties in the message format, plus they use the Mastodon client API instead of ActivityPub client-to-server. Their dominance wrt running Mastodon instances means they have a big say in how Fediverse evolves.
Luckily the project team is open-minded, and mostly on the same page to others wrt fediverse innovation.