This term was first used in a community-run Mandriva Linux help forum to describe a long-winded (and possibly overly explanatory) post. It is named after a user (gowator) at said forums who's posts almost always reflected this definition.
Currently there is a debate regarding the original creator of the term between two members of the forum. It is not likely this issue will ever be resolved.
"My, that post was quite gowatorial! Perhaps you should shorten it."