
orz (sometimes seen as _ ̄○, OTL Or2, Orz, On_, OTZ, O7Z, Sto, Jto, _no) is a Japanese emoticon representing a kneeling or bowing person, with the "o" being the head, the "r" being the arms and part of the body, and the "z" being part of the body and the legs. This "stick" figure represents failure and despair. It is also commonly (mis-)used for representing a great admiration for (sometimes with an overtone of sarcasm) someone else's view or action. This spawned a subculture in late 2004 .[3] Though people generally use the pictograph to show that they have failed and/or they are in despair, some users use it to imply being doubled over in laughter. It is not to be read phonetically; the letters are spelled out. Orz should not be confused with m(_ _)m, which means an apology.
Orz is associated sometimes with the phrase "nice guy" — that is, the concept of males being rejected for a date by girls they are pursuing with a phrase like "You're a nice guy," or "I'd like to be your friend."
On imageboards, it has been used not only for failure and despair, but also as a symbol for the kowtow, illustrating a person bowing down in worship of a certain picture that was posted.
Reference :
http://en.wikipedia.org/wiki/Emoticon