Google did commence the process of providing an API for osCommerce but never finished the job because it is in fact complex.

Furthermore because it is a Checkout and Google requires that you do not require customers to create accounts to use your store, it means that many small businesses that pay Google good money via ad words to find customers end up being a middle man. The customers get the goods and Google gets the customers. All the store gets is money. And money is not enough.

In fact Google Checkout is close to a drop ship model where sites both take the orders and deliver them and Google takes the customers nd the money (passing on the site’s share). Very clever really – for Google.

So while the reasons are different I too discourage my customers from bothering with Google Checkout at this stage. I see it as an insidious process that is not in the best interests of anyone looking for “customers” aka repeat business.

The big players have nothing to lose by using it, the small players have everything. And don’t tell me about lost sales, I believe that as much as I believe that having “Hacker Safe” increases sales. Another of my pet hates for small business.

Patrick Chanezon, Google API Evangelist
http://wordpress.chanezon.com/
http://code.google.com/apis/checkout/