Complex sentence: Behavioral retargeting (also known as behavioral remarketing, or simply, retargeting) is a form of online targeted advertising by which online advertising is targeted to consumers based on their previous Internet actions, in situations where these actions did not result in a sale or conversion.
Split into simpler sentences: Behavioral retargeting (also known as behavioral remarketing, or simply, retargeting) is a form of online targeted advertising by which online advertising is targeted to consumers based on their previous Internet actions. A common use-case of retargeting is situations where a website visitor's actions did not result in a sale or conversion.