It was a matter of time.  After years of providing free readership to ecommerce sites, Google Shopping is going CPC.

The announcement came this morning that there would be a fundamental change to its Product Search and Product Listing Ads programs (originally known as Froogle).

Beginning June 1st, Google will begin to phase out Google Product Search (the free, data feed-driven product listings that show up on Google.com Search Results pages and under the “Shopping” tab) in the United States.  These ads will be replaced by a paid format called Product Listing Ads and managed through the Google Adwords interface.  Learn more about Product Listing Ads here.

The complete transition is expected to be in place by October 1st.  However, if you act now and create Product Listing Ads before August 15th, 2012, you will receive a monthly credit of 10% of your total Product Listing Ad spend through the end of 2012.  Additionally, merchants who are currently listed in Google Product Search can receive $100 Adwords credit towards Product Listing Ads – Also if completed by August 15th, 2012.

Google’s aim, along with increased revenues, is to increase the data quality and in return create a better shopping result for users.

In addition, merchants can participate in a program called Google Trusted Stores, which would provide a badge for ecommerce sites that would provide company background information ratings and more.  This program would offer a sort of insurance to the user.  For sites that participate in this program, Google would offer a $1,000 lifetime purchase protection guarantee per shopper.

Look for changes occurring on the Google Shopping interface as well.  Starting today, Google has stated they are experimenting with a new commercial format.

The impact of these changes will certainly ripple through the ecommerce world profoundly.  Check back as Vertical Rail will continue to share the news and developments of this announcement.

Click here to read the announcement on Google’s Commerce Blog.