Meanwhile, eBay began by building the online auction and collectibles market, and it's hard to see anyone ever displacing it there. But along the way, it built a worldwide community of millions of people regularly buying and selling, from established companies to spare-room entrepreneurs to old ladies cleaning out their china cabinets.

In my opinion, through a prism of the shopping experience, here are some of the ways eBay is better:

Product Range: Once you stray out of media and electronics, Amazon is stocked mostly with lower-end utilitarian products. Despite its large number of "partners," major categories like Home, Garden & Tools and Clothing, Shoes & Jewelry are, in fact, Wal-Mart quality. Its purchase of Zappos.com helped in the shoe department, but that's one niche.

Try searching for a prestigious furniture brand -- say Henredon. Amazon has four matches; eBay has 346. Or a popular style, like Mission oak. Amazon has plenty of matches, all made of cheap "oak color" veneer. eBay has signed antiques and high-quality reproductions as well as the cheap stuff.

Or, try a designer fashion name like Ralph Lauren ( RL). Amazon has mostly the mid-range department-store selections. eBay has that, plus a huge selection of the brand's high-end labels, vintage and couture, runway fashions and designer samples, "lightly used" merchandise, and last-season bargains.

To be fair, some of the better quality stuff is there on Amazon, but it's just too hard to find. That's where usability comes in.

Usability: eBay simply has superior search capability. eBay asks all the right questions -- on size, color, shape, fabric -- to pinpoint what you're looking for. Amazon does that too -- sort of -- but it's a tedious and time-consuming process. And on Amazon, the best matches are likely on an "external site," which wipes out the whole benefit of "one-click" checkout.

Product Presentation: The whole eBay community ethos demands that sellers provide exhaustive descriptions, detailed specifications, photos from every angle, personalized page design, and your questions answered on demand. Amazon encourages one photo and a description so terse you have to worry about taking a chance on anything that costs more than $19.95.