Threats against ActivityPub

Evan Prodromou had an important post a few days ago, arguing for backwards compatibility with future ActivityPub work and discouraging competing protocols. I found some things to agree with in his post, but I’m less certain that there is a single path forward. On Bluesky and others, Evan writes:

We get exponential growth based on having one protocol, not a half dozen. I think Blue Sky, Nostr, and others are a threat to ActivityPub breaking out and becoming ubiquitous. There can’t be multiple winners. I often reference Metcalfe’s Law in this regard; one big connected internetwork is much better than 3 or 4 disconnected ones.

Maybe. But the web has always been more muddled than that. We have multiple feed formats, like RSS, Atom, and JSON Feed, and it’s okay. We have multiple blog APIs, like MetaWeblog, AtomPub, and Micropub, and it’s okay. We have multiple social web notification mechanisms, like ActivityPub, WebSub, and Webmention, and it’s okay.

What makes it all work is that the web is the network. The fediverse is one aspect of that network. If we go too far elevating the fediverse as the only ubiquitous network, it risks disconnecting it from the blogosphere (!) and the rest of the web. Already I’d argue that some Mastodon decisions have isolated the platform, such as loading content via JavaScript so there are no longer basic HTML web pages for post permalinks.

ActivityPub is a huge success story. Yet there are still good ideas to pull from competing protocols. For example:

  • Bluesky is using domain names for user identity. I’d love to see the fediverse adopt this in addition to email-style identifiers.
  • Nostr is less verbose than ActivityPub. I’d love to see cleaner ActivityPub responses without JSON-LD.

If we never let other protocols get off the ground, there would be fewer experiments to help push ActivityPub along. It’s also curious that with Mastodon so well established, Bluesky recently hit 1 million users as an invite-only beta. How? Answering that may help Mastodon and ActivityPub adoption too.

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Manton Reece @manton