An audience profile based on observed activity, created to understand your audience, set objectives, and facilitate achievement of those objectives. Models are different, depending on what you are training them to achieve. For example, a model could be created based on purchasing activity from your website, helping you to reach an audience exhibiting similar behaviors; a model based on people who have landed on your product promotion page, helping a publisher to understand behaviors of visitors; a model based on people who have viewed your video ad more than 60% to completion, helping you understand behaviors of engaged visitors; a model based on people who look like your offline customer to drive online conversions.