Yeah, but what pays for search? Remember the early days of Google, they got the search tech right, and returned the best results, but there was concern how they would make money. They lucked in AdWords and took over the online advertising industry. Commerce is one significant (if not the main) source of the ad dollars.

They have buy competition though. I have read (and it seems plausible to me) that most people go directly to Amazon.com when they know what they want to buy already, and they only search Google for things to buy when they don't know.

I myself limit my online buys to Amazon because it's more convenient than setting up a new account for each individual vendor. I don't even care if I pay more at Amazon. It's safer and more convenient.