Comments of thanks

Question

The help section of the site states

Please do not add a comment on your question or on an answer to say "Thank you". Comments are meant for requesting clarification, leaving constructive criticism, or adding relevant but minor additional information – not for socializing. If you want to say "thank you," vote on or accept that person's answer, or simply pay it forward by providing a great answer to someone else's question.

Can anyone speak to why this kind of comment is explicitly discouraged?

I've observed that

1. These comments happen anyway
2. They don't harm the site in any noticeable way
3. They help make the community a friendlier place

I understand the idea behind this; accepting an answer and/or up-voting it is the suggested method of saying "Thanks" but what is the harm in adding a comment of thanks as well? Would there be any harm in removing this paragraph from the help section?

Answer 1

Well, lets just say that Gilles is willing to have a thanks each time someone finds one of his answers helpful. You know what would happen?

Not very useful, right? How can he find what needs his attention vs everything else? He can't. His inbox effectively becomes useless for all purposes. That's why noise (any kind) is actively discouraged and on some cases directly blocked. Respect every people inboxes, don't fill it with noise.

Answer 2

One of the main problems with forums is how miserable they are for future readers; a lot of Stack Exchange policies exist to try and keep posts useful long-term. This is why questions get closed and merged, rather than repeating information over and over on new posts, and why duplicate answers get removed and long comment threads get cleaned up. "Thank you" comments make the person being thanked feel good, potentially, but are just unhelpful lines that need to be scrolled past for every future visitor with the same question. Upvotes serve the same functionality, while helping sort answers, and don't waste space or get in the way.