2015-06-23 UTC
# 
csarven rel=in-reply-to was first and arguably most notably (to the best of my knowledge) implemented on the StatusNet platform for "conversations", i.e., a thread of status updates in reply to one another across StatusNet instances. The original intention was to link an hentry URL to another hentry URL (which may or may not be the full doc or a fragment in a doc). In parallel, I have used in-reply-to on