I think there may be something in that.
My most-upvoted comments have been (a) comments to the root article, not sub-comments; and (b) generally rather short and 'flip'. Apart from that, I can't find any pattern in which comments get upvoted and which don't.
I don't (I hope) post echo-chamber comments; if everyone already agrees with me, there's no point in posting.
I post what I think are insightful comments, that stick on 1 forever; and comments that I know are controversial, that scoop 20 upvotes in 10 minutes. I also occasionally post vacuous, "witty" one-liners that, to my surprise, garner lots of upvotes.
I don't post for karma; I post for sub-comments, i.e. I want to discuss stuff. I don't like long comment threads on HN though; so I never post more than one or two replies to my own thread.
EDIT: just as I'm being downvoted. The echo chamber cannot be called out.
EDIT: the guideline of not discussing downvotes hardly applies here!!
>Please don't comment about the voting on comments. It never does any good, and it makes boring reading.
edit
>the guideline of not discussing downvotes hardly applies here!!
Why? Your entire post was "You'll be downvoted for saying this."
Do not get me wrong, there is some very interesting stuff there but half of gathering chunks of upvotes is not rocking the boat and saying anything that goes against the echo chamber.