Selective translation from 十八摸狗日报 (above image also from there):
“orz” (also written as Oro, Or2, On_, Otz, OTL, sto, Jto, ○|￣|_) is net lingo (or an emoticon) that was created in Japan in 2004 and has since become adapted by the Chinese and Taiwanese. It represents for a person facing left kneeling on the floor. In its original home of Japan, it symbolized an apologetic kneel where “o” is the head, “r” is the arms and torso, and “z” is the legs.
“orz” in Taiwan is linked to the Culture of Nice People (好人文化). Being called a “Nice” person in this regard is like a girl telling you, “Oh, I think you’re a very nice person. I believe you can find a better girl than me. I only want to be friends with you.” In other words, a way for girls to reject guys.
And now, it’s been adapted to become [translation note: only a partial selection has been translated]: