This article starts out idiotic (of course it burns more calories to run than walk, duh!!) but the formula for calories burned while running is interesting. I had never heard of net calories burned, but it makes sense, and the number closely matches the data on my Map My Run app. I think this is the figure they are using. They didn't mention how weight, mass, BMI play into overall calorie burn, and many of the running apps ask that for your profile data, presumably to use in calculations. Does this mean it is negligible? Who knows... science is very confusing. They also didn't mention how taxing running can be on your joints compared to walking. Now that I think about it, this isn't a very complete article. :)
This formula is helpful nonetheless: net calories burned is 0.63 x your weight in lbs. (or 0.75 for your total calorie burn, without subtracting your normal metabolic resting burn).