As I said at the beginning of the chapter, e-commerce stores, in general, are websites where anyone can browse through a number of products and then use a shopping cart to make a purchase. Also, most e-commerce stores offer some kind of online payment integration, which allows every visitor to make and complete a purchase quickly. Additionally, sometimes there's even a backend inventory management system (an online warehouse of sorts) to make backend business management easier and integrated with the website.
Now, the best thing about this line of business is that you can actually launch an e-commerce store with WordPress, which, in my opinion, is simply incredible. As a former website developer, I remember how expensive and time consuming it was to build such a store from the ground up. Now, you can just install WordPress, get a proper theme, buy/download a specialized e-commerce plugin, and you're good to go. This is a prime example of how technology meets the expectations...