Retargeting (Defined as remarketing by Google) ads display to people who have already visited your website and who have already established themselves as prospects. According to Google, retargeting increases conversion rates 50% to 100%, or more.
Site targeting displays your ads on a group of relevant websites selected by you and us. Site targeting enables you to deliver a message to your potential customers, not only generating leads but also grabbing the attention of potential customers and raise awareness related to your business.
Contextual targeting is keyword-driven and displays ads on websites with content that matches the keywords the display campaign targets. When your ad displays, it is likely to be relevant and timely, improving the likelihood of your ad getting clicked.