Online Shopping

Since moving to the boonies I've started doing a lot of online shopping. We live just way too far from any stores. I've noticed that many of these stores are run by moms trying to find a way to make money so they can stay home. I think that's wonderful. I really wish I were that motivated. Anyway, when you're doing a lot of online shopping you start to learn about the various systems sites use for their payment processes, including authorize.net. I wonder how they decide which format to use?