Following his Day Camp 4 Developers event, Cal Evans needed a way to release the videos and materials from the day long even to those that paid to attend. Obviously, a download link just wouldn't do, so he went looking for something a bit more powerful and WordPress-y.
It sounds like such a simple thing; just put them up for download, right? Not really. Let's look at the actual requirements: Shopping cart to allow me to eventually sell the videos, a way to let my existing ticket holders "buy" them for free. (Coupon codes), a way to keep the real location of the files hidden so people don't just go download them. Those were the biggest items. Beyond that I was willing to either sacrifice or code it myself.
After searching around and trying out a few solutions, he decided on eShop ("it's good, not great) a WordPress plugin that lets you set up a quite configurable ecommerce website. It also includes some basic statistics features, uses the custom post types to configure products and lets customers sign into the site to handle their own options.