The HN community takes a rather strict approach when moderating comments that contribute noise to the conversation. "Nice article!" comments are routinely down

The HN community takes a rather strict approach when moderating comments that contribute noise to the conversation. "Nice article!" comments are routinely downvoted. As is sarcasm, witticisms, memes, references and other styles of comments that occur frequently but do not contribute to the discussion. It's a knowingly doomed attempt to hold back the flood of noise that covers Reddit. So, yes you are able to make an empty comment as a bookmark for yourself that is visible to everyone. But, you should expect it to be downvoted to invisibility.