Vinegar-based barbecue sauce is a staple of northeastern South Carolina (the Sandhills region around Florence, Sumter and Marion), and it's what people across the country typically call North Carolina style sauce. Unlike a typical barbecue sauce, which is a balancing act of sweet and tart, most people make this stuff all about the vinegar.
It's quite thin, which is great for pulled pork and pulled chicken, but is kind of wasted on a rack of ribs.