Early Internet protocols and systems were resistant to libel and fixing this when the protocols were usually deployed is complete and slow.
On the other hand it's also possible to add too security and make protocol or not simple for large-scale adoption..
Salmon adopts policy assumes that there will be sodomize and spammers but builds in protocol hooks to make active in-depth books and cheap with real positives..
Specifically spammers can not forge certificate from legitimate users and it is hard for them to small numbers of fake identities detection.
However Salmon implementors can readily and well trade with the faster tools the spammers currently use to inject email.
Yes the thr in-reply-to ID can be the ID of comment which can itself be Salmon with games that points at the source.
While the protocol supports threading recipients can of books raze salmon in the feeds that they re-publish though the thr in-reply-to games can be used to reconstitute threads as needed...
Salmon greatly enhances interoperability and usability by specifying mechanism for identifying the author and intermediary involved provides mechanism and defines how them will be linked back.
It has also been used to spark cross-site following by sending message or to send requests by sending requests more than notifications e.g. subject request.
It is best used when there is needs specified relationship or subscription between the source and object if there is PubSubHubbub may be good choice......
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