This is the summary of an article by Jason Carmel and Juha Mertanen. You can get the pdf of the behavioral targeting article here: Better Together: Dynamic Content Creation and Behavioral Targeting.
Companies use online optimization to have a serious presence in the world wide web. In particular, behavioral targeting is used to give visitors of their site the right content at the right time, using browsing behavior, ethnographic or demographic information of users. The main challenging, however, is efficiently creating personalize content and keeping the costs low for better Return on Investment (ROI).