There's no network effect having everyone shop at Amazon or a competing site. But on a site like eBay, hundreds of thousands of people around the world are buying and selling in one marketplace. That scenario is more compelling to you, and so it has inherent barriers to competition. The minute they find something that they like and it works, they stick with it, because life is too quick and hard to spend all day comparing. But it's important that you fulfill what you promise a consumer, because the minute you do that, they stick with you.
People are loyal.
And in Europe, the consumer is much more loyal than in the United States. The beauty of the network effect is that once I have it, I keep it because a lot of businesses, like the infrastructure players, have no network effects. Amazon, for example, was not a first mover. It was, perhaps, the fifth seller of books in the market. But look at Amazon.