Contraction of Ok, thanks, bye.
Used when you want someone to shut up (you're not exactly trying to be polite,) yet it's not considered as an insult like STFU. Also it can be used when answering a stupid n00b question, or after scolding someone.
I'm not arguing anymore. kthnxbai.
Stop that or I'll ban you. kthnxbai.
^ above isn't as insulting as STFU N00B!
Literally "Okay, thanks, bye". Commonly used when short words and phrases are needed, as in when chatting and texting. Can also be used to quickly end a conversation, usually in a rude fashion.
Signalls the ending of a conversation. Usual follows a distinct point made. k=okay thanx=thankyou bai=goodbye. Kthanxbai replaces the need for "thats the end of it".
Msn Conversation:
Jeremy: Im so much cooler than you.
Andrew: No your not i am much cooler that you idiot.
Jeremy: how rude
Andrew: Just shut up you noob im cooler kthanxbai
Okay, thank you, goodbye. Abbreviation thereof. Commonly used in a facetious or sarcastic manner to emphasise the rapidity with which the sayer wishes to both win and then leave the conversation.
Person 1: *ninjaloots items*
Group: WTF?!
Person 1: kkthnxbai! *logs*