This dissertation addresses some interesting questions related to exclusionary contracts and advertising choice. The first paper develops a model of long-term contracts as barriers to entry with differentiated products. It shows that if an incumbent firm can hold the consumer surplus in the pre-entry period hostage, he can sign the buyer up for a long-term exclusive contract regardless of the degree of product differentiation. Even though entry by an equally efficient firm is blocked, the contract still increases welfare if the incumbent's and the entrant's products are close substitutes. The model is further extended to include more periods, uncertainty, discounting, and no commitment power. When the incumbent is not able to credibly commi...