This dissertation studies three different dynamic environments and trade-offs that arise from the dynamic structure of the problem.The first chapter considers a dynamic pricing problem. The Internet allows sellers to track "window shoppers," consumers who look but do not buy, and to lure them back later by targeting them with an advertised sale. This new technology thus facilitates intertemporalprice discrimination, but simultaneously makes it too easy for a seller to undercut her regular price. Because buyers know they could be lured back, the seller is forced to set a lower regular price. Advertising costs can, therefore, serve as a form of commitment: a seller can actually benefit from higher costs of advertising. Based on this framework...