Rod Richmond discusses how to prevent leakage of ecommerce sales to Amazon. He outlines a 4 step process: 1) Measure the extent of leakage using tools like Auction Insight reports and monitoring search results, 2) Budget advertising spending between Google and Amazon Ads based on the measured leakage, 3) Prepare for the differences between Amazon Ads and Google Ads such as winning the buy box and limited bid strategies, and 4) Prevent further leakage by reevaluating direct customer relationships and using tools like Google Universal Checkout.