That's what they do so well. Several times a day, I end up visiting Amazon.com, browsing books, just hoping that they recommend a book to me that sounds so good it gives me an excuse to buy it.

If you go to Amazon looking for something very specific, you'll find it pretty quickly. Entering almost any book title or author will return very accurate results. You might be surprised, but that's actually a remarkably difficult thing to do well, and Amazon does it with amazing precision.

Even more difficult than that, however, is to help people browse, and this is where Amazon really shines. More often than not, I come to Amazon looking for a book on a particular subject or idea, and sometimes, I have very little in the way of search keywords to go on. It takes very little time for me to arrive at a book that satisfies the need I was looking for.

Finding specific items by searching for the name is comparatively simple. It's just a matter of matching the search text with the text of the products. But allowing people to browse around is based on more than product data; it comes from community. Using Amazon to find books that I'm looking for, I'm using their product recommendations, which are based on orders by past customers. It's based on the items in customer wish lists. I use the reviews to gauge how good a book is, and to seek out direction from people who seem to know more about the subject matter than I do.

All of that customer data is Amazon's biggest asset, and they leverage it very well. That's why I'd be willing to bet that Amazon's stock is probably a pretty safe investment, at least into the foreseeable future.

In online marketing circles, getting a customer to make a purchase is called "converting", but I like the term closing a whole lot better. If you're good at something (and honest), then you don't need to use a euphemism to describe what you're doing. Amazon is a salesman, and they close me at least once a week. They can guess at what I might want to read better than most of my friends can. The "sales associates" walking hurriedly through Borders desperately trying to avoid eye contact with customers don't have a prayer.