Nobody is expecting Google to relent on its drive to turn Google Checkout into a major payment system after grabbing a 6% market share in 2006. It’s already free through 2007 and Google is pretty much offering continuous Google Checkout promotions. So what’s left?

Increase conversions (more potential buyers) by calling out Google Checkout in search results and enlarging the AdWords badge.

Google is now experimenting with Google Checkout buttons on AdWords as reported earlier this week by Google System (their image on the right). Now Google has come out on its Google Checkout blog, admitting the experiment.

The first change we’ve made is a limited test of new Google Checkout badges on AdWords advertisements. Google runs experiments all the time to test new ideas and improvements, and Checkout is no exception. The experimental badge we’re testing uses a Checkout button rather than a cart image to identify Checkout merchants. This test will appear on a very small percentage of queries and we look forward to learning from experiments like this so we can ensure Checkout continues to deliver value to everyone — especially our users who are eager to find fast, secure places to shop when they search.

Why does this matter for online retailers? Bigger button = more eye catching = more conversions = more bang for your paid search Google dollars. Not offering Google Checkout? Do a few searches in Google using your top products as keywords and watch your competitors take your buyers by offering this convenient checkout method.