@colinsmatt11 @alex Actually, Mastodon implemented Linked Data signatures back in 2017. They're using Ruby JSON-LD library but for many other languages similar library simply doesn't exist, that's why everyone uses HTTP signatures.
I proposed an alternative here: https://codeberg.org/fediverse/fep/src/branch/main/feps/fep-8b32.md (the document recommends JCS instead of JSON-LD/RDF which is easier to implement)
Also, some people believe that signing activities is bad because you can't deny that you wrote a post you wrote.