To my experience, "context-heavy communication" is rather subtle on HN, more of an inside joke if anything. I can't think of a case where a comment would seem off-topic if read by a transient commenter; it's just that over time, you start recognizing other regulars and their views on some topics, and sometimes you may remark on it. Like, I recall participating in comment threads that branched off into "I recall you saying X on a related thread some time ago; could you elaborate on that?" somewhere deep in the discussion. Or, I know to not reply about topic Y to a particular commenter, because we've been through a long discussion about it some time ago, and essentially agreed to disagree. Or, someone will joke that it's time to submit and upvote some Erlang stuff to HN, and the joke mysteriously stays upvoted because, well, it's an inside joke.