Barbecue is probably the world's oldest cooking method and that is the only thing about it that is beyond dispute (see my companion article on The Story of Barbecue and the Origin of the Word). Everything else about barbecue is controversial and in some quarters likely to start a fight.
Folks can't even agree on how it is spelled. Is it Barbecue, Barbeque, Barbaque, BBQ, B-B-Que, Bar-B-Q, Bar-B-Que, or Bar-B-Cue? For the record, linguists and historians generally agree that the proper spelling is barbecue because it is derived from the word barbacoa, and that other spellings are colloquial.
Some folks think barbecue is hamburgers on the hibachi. Others say no, that's grilling, not barbecue. Some say barbecue is only pork. Some say it is only beef. The Kansas City Barbeque Society (KCBS), which sanctions hundreds of competitions, says it's both, and chicken, too. Others think it is only whole hog. In North Carolina it is only hog, but the state is riven in two parts over what part of a hog can be called barbecue. Some say it must be whole hog, others shoulder only. And their neighbors in South Carolina aren't even allowed to enter the debate.
Some say it is only cooked outdoors over live fire, in which case there are probably only a dozen barbecue restaurants in the US. Others say it must be smoked with indirect heat in which case the African American slaves who created classic Southern barbecue were cooking something else when they dug pits and put the meat above glowing embers.