When many people talk about and think about barbecue, they're talking about smokers and smoking food. Without a bit of the smoky taste from a low-and-slow cook using coals and some sticks to create a masterpiece, you shouldn't call it barbecue. At least that's what many people say.
There are many techniques for smoking food ranging from cold smoking to warm smoking to hot smoking and even smoke roasting. The equipment ranges from offset to drum smoking to pellet smokers to gas and electric smokers. There's a place for everything. The important thing is that the chemistry involved in creating smoked food requires that you use different types of woods and different techniques based on what you are smoking. This is really what makes this part of cooking outside a true art form.
Growing up in the suburbs outside of New York City, I always thought that you went TO a barbecue. It wasn't until I started working for a southern paper company (Westvaco) back in the 1980s that I learned that you ATE barbecue. I had always thought that a barbecue meant going to someone's house and eating hamburgers and hot dogs cooked outside. It was a treat when one of our relatives of Italian descent donated ziti and meatballs.
But that's not barbecue. Barbecue to those that know better is about cooking food at a very low temperature for a very long time in a chamber that may or may not have a fire in it, but features some from a fruit wood like apple or peach or a harder wood like white oak or hickory or pecan. You cook the food, like meats, far longer to a far higher temperature than you would in the house. The end result is surprisingly juicy meat with a flavor that you'll always remember.