I agree with Flimm that *OP* doesn't need to be the FAQ. But I do think it should be in [the glossary][1].

And it is in the glossary! It's somewhat confusingly under "Ask Ubuntu/Stack network specific terms" (even though it's not really specific to SE or AU).

The entry for it says:

> ### OP
> 
> `OP` = Original Poster

Also, people should feel free to ask us what that and any other jargon means (as well as to search for or look up the term, as Flimm suggested).


  [1]: http://meta.askubuntu.com/questions/3670/i-saw-something-in-chat-i-dont-understand