If you are referring to 'updog', its a joke word the chat censor uses to blank out other IM's like 'yahoo', 'skype'.. etc. Its not a real thing, just a product of the admin's senses of humour. It used to say 'moooooo' a while back and has had a few other incarnations over the years. 'Updog' is the current one.
Ls x