There are cases when I write a comment addressed to me just to say "yes you are right", "thanks, fixed" or "taken into account" etc.

It would be nice to have a simplistic way of doing so without adding a comment - like, have a button against each comment addressed to user pressing which sends a corresponding note to the comment author. Like, instead of saying "agreed", I press the corresponding button near comment and the message shows up ni Inbox and corresponding mark is displayed on the comment in the public.

This would both clean up the comments somewhat and improve the feedback (I would personally like to know that user who I replied to have appreciated the comment).

It is counter-prodctive to add "dismissed" mark because if someone does not agree with something they is expected to express it.