Macbook Pro Retina Storage

I just wanted to ask a quick question to cure my curiosity. I just purchased the 15 inch MacBook Pro with Retina display and was curious about the storage fluctuations that I am seeing. In fact, I have always been curious about how this works. When I first started up the computer, I had 499 gb of 512 gb allowed for usage. After a couple hours (with no installations or media additions), I was down to 478 gb due to "other" storage of 14.47 gb. I have seen this before on other macs that I have owned and I just thought I would ask what makes up this "other" category. Also, is it normal to have this much allocated to that area?