Clearly meant to be a "go humor" page. But actually, the topic is not completely without merit for serious discussion. Putting aside the language issue (I play in the English room on KGS so I don't worry that opponents don't know "hi"), there is a question of the purpose of saying "hi" and "thanks", which seem to me to be the bare minimum of civil communication.

Having considered this, I decided that "hi" is alright, but not what I want to say. What I really wish to express is that I hope for a mutually enjoyable game. Summing this up in as few words as possible I always begin games with "enjoy!"

I always end games with "thx". I never say anything else unless a dispute arises, which is rare (has only happened when I refuse an undo, which is my right!!!!---don't get me started).

I also no longer play with any player who doesn't at least say "hi" and "thx" (or some equivalent). It just seems rude not to make a small effort to be civil.

I typically say something like "Hi, have a good one." It's a bit idiomatic, but seems alright to me. For the end, I dislike "thx" myself. It seems worse than nothing. I try to create a complete sentence out of it "thank you very much for the game." I also try to do this before the last "Done" is clicked, so that I can be assured it was sent before the end of the game when the result is final. My own little way of saying that regardless of the game result, I enjoyed the time spent playing the game.

ChiyoDad has an interesting take on greeting your opponent. Since reading this, I've started my games against my close friends with an emphatic 'KIAI!!!!'

http://chiyodad.blogspot.com/2005/09/how-to-greet-your-opponents.html