The definition of e-commerce is very easy: a place where we can do purchasing, selling, and trading behaviors on the internet is e-commerce website.

Bestbuy, Target, and ebay are good examples of the e-commerce website. On the other hand, most online game sites sell their game service on the internet. With the definition above, they are e-commerce site, but lots of the navigation are the introduction of their products (the game itself.) Like Magic: The Gathering Online, Magic is a card game and it sell virtual card online, but we don't know it when we first access to the link. If you want to buy the cards, you have to click the "onlind card shop" in the middle part of the page.

We can find that the e-commerce of the entertainment site uausally doesn't appear as an e-commerce site. It is more important to attract the user first, so the introduction of the entertainment itself has a bigger part. Except this kind of site, most e-commerce site could be identified by their products in the homepage. We can know they are selling products easily when there are many price numbers or the explaination of quality. When we find that the site is doing the advertisement and want us to purchase, that could be the e-commerce site. Thus, what makes us think it is e-commerce site is the "tone" of the site. That's why the design is important, because user will pay attention on what we emphasize first.