* Assume the person responding to you hasn't read the article, and has only briefly scanned your comment while mentally composing their reply.
* Anything abstract is going to get misunderstood; keep it concrete but vague.
* There is no consistent relationship between quality of a comment and how people respond to it.
* You can write a reply and then erase it without sending, and that's the best thing to do in most cases.
* When in doubt, collapse the thread and move on.