Carolina BBQ is usually pork rubbed with a spice mixture before smoking and mopped with spice & a vinegar liquid before smoking. This is probably the oldest form of American BBQ. The wood is usually hardwood such as oak or hickory.
North Carolina has two styles: Eastern and Western. Eastern North Carolin is a thin sauce made of vinegar and spices. They are typically cooking the whole hog with his one. Western North Carolina uses vinegar-based sauces that include tomato which we usually used on pork shoulder.
South Carolina has inherited the two Northern Carolina Styles. You will find along the Savannah River a peppery tomato or ketchup-based sauce is common and throughout Columbia to Charleston, they use a "Carolina Gold" sauce made of yellow mustard vinegar, brown sugar, and other spices. This is what people refer to as "Southern Carolina BBQ"