↳ In-reply-to » is the first url metadata field unequivocally treated as the canon feed url when calculating hashes, or are they ignored if they're not at least proper urls? do you just tolerate it if they're impersonating someone else's feed, or pointing to something that isn't even a feed at all?

@zvava@twtxt.net That was my greatest concern with how it is currently handled, I’m afraid to break threads even by fixing a typo.

Handling it via the pod might work but I think it’s not the best approach, external feeds and clients don’t usually use a pod api but their own implementation, so any workaround won’t work there.

That’s why my proposals addressed those issues:

• the idea of using a “key” instead of the url (with the url as a fallback), the key could even be a public key so it can be used verifieable in crypto functions
  
• using the timestamp to prevent content changes to break threads (plus being simpler to implement)
  
• using an explicit thread reference with an alternative subject format (like [#THREAD_ID] Hello world and replies with (#REPLY_ID) Ahoy) so the content can change without affecting the thread reference, and anyone can use their own schemes freely