Originally branding was done with an iron. As denuseri said, the scarring usually faded or scarred in a weird pattern. Plus, burns are at high risk for infection. It would have to be something that you could care for. These days, most people prefer tattoos or even piercings. I have a scar that was created during blood play (touchy subject. I know) and even though the cut was completely straight, it did not scar straight. Cutting the sub for branding is also an option. In all honesty is was the option we were going to take. The one cut we made was kind of a tester... And it was for experimental purposes as well. When we saw the final outcome after healing, we decided that a tattoo was the best route to go. Also, as denuseri said, tattoos stay fresher and heal better given that you find a good artist. Ask to see their work. It never hurts to be too safe. I gave heard Doms says they felt tattoos as a brand isn't given by the Master (unless they're a tattooist) and it takes away from it, but I disagree. If you both agree on what's being tattooed, it still maintains its significance.