The thing I really don't love about ATProto is its decision, or that of its dominant implementation to enforce a schema ("lexicon") on content, limiting interoperation between disparate software. This violates the Old Internet idea of software being liberal about what it accepts.

For a concrete example, I tagged a Lemmy community in a Mastodon post today. Lemmy is Reddit-like and Mastodon is Twitter-like, but it displays reasonable on Lemmy using the first line of the post as a title and expanding to the attached image when clicked in the default Lemmy UI. I can also post a long-form article on Wordpress (with a plugin) and have it show up in Mastodon even though it has a short character limit by default.

That's an incorrect assessment

Lexicon schema are not enforced, they are a tool for social coordination, and most implementations are very liberal in what they accept

https://www.pfrazee.com/blog/lexicon-guidance

> isTool: true; isRule: false; meaning: undefined

ActivityPub by contrast lacks such social coordination and many apps are reusing the same schema for very different concepts, leading to its own form of over-complexity