- No e-commerce sites charge money on any app stores for users to download their apps since they want the largest audience possible shopping them.

- Google Play only takes a cut of in-app purchases of digital goods and not physical things. Most e-commerce companies would not survive if Google took a 30% cut of everything sold since margins in many industries are in single digits (electronics/computer parts for example are generally less than 5%).

1. There is little money in google play.

2. If the retailers are big enough, they can easily strike deals with carriers/ phone manufacturers. Or, like Amazon tried, create their own market place.

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.

Read the story.

Search for [Pure One Mini] (pure is the manufacturer, one mini is the product name, of a DABS portable radio.) you get a bunch of results that just aren't relevant. You get accessories for this device, you get accessories for other devices from this manufacturer, you get other devices from this manufacturer, you get devices and accessories from other manufacturers. You have to use the side bar to restrict the products to those from Pure. But you still get all the Pure product line, and there's no way to further restrict the selection.

Back when people were still selling the Sansa Fuze: Search for eg [sansa fuze 8GB] then sort by price. You get dozens of pages of cases, then leads, then chargers for the sansa fuze. And Amazon's next page only allows you to advance by single pages, you can't jump forward by 5 pages at a time.

Search for [microwave oven], chose a department, and search by price, and you'll get a billion things that can be used with a microwave oven (timers, cookware, books) and then actual microwave ovens. You have to do further refinement using the side bar.