What ketchup is to Americans, I think Gochujang is to Koreans. Gochujang is a red pepper and bean paste that will fire up your taste buds. It is nothing like ketchup, other than it is red. Gochujang is not for dipping or as runny as ketchup, but it seems like gochujang is in 25% of all Korean dishes. (okay, maybe an exaggeration). But it seems like just about every dish at the Korean market deli is red with red pepper or gochujang.
I do think gochojang would be good in a hamburger patty, maybe a little on a hotdog, but never on fries.