Machine learning can be applied to many different aspects of a business. In marketing buyer personas are used to outline representations of your ideal customer. This helps marketers adopt a unified understanding of who your business is trying to attract and relate that understanding to real life examples. 

Classifiers can help identify which set of categories a new observation belongs to. In this example we are using classifiers to determine which persona a new visitor to your site would be classified under. Knowing this information could help customize your site and tailor different sections and offerings to the specific person looking around.