An AdWords remarketing tag is a small snippet of code that is placed on a website to track and target visitors who have previously interacted with the site. This powerful tool allows businesses to show personalized ads to these past visitors as they browse the internet, increasing the chances of converting them into customers. By using the AdWords remarketing tag, businesses can effectively reach out to potential customers who have shown interest in their products or services, making it a valuable component of any successful digital marketing strategy.