The following is a direct quote from the terms of service you must read and agree to before signing up for an account:
"The Google Services are made available for your personal, non-commercial use only. You may not use the Google Services to sell a product or service, or to increase traffic to your Web site for commercial reasons, such as advertising sales."
It seems to me that "posting" items to sell and/or any of your eBay pages/listings would be in direct violation of their user agreement.
Am I missing something here?
nightowls