e peering, content delivery networks such as Akamai, network-based spam filtering, and blocking Web sites known to be the source of viruses, attests to the extent to which the Internet is already far from "neutral." On a more fundamental level, adoption of a more permissive approach to end user restrictions would parallel the shift in the vision of the ideal form of competition that has taken place under the antitrust laws. Prior to the mid-1970s, the Supreme Court took an extremely hostile view toward vertical integration that combined manufacturing and retail delivery under the same corporate umbrella, as well as vertical contractual arrangements (such as exclusive dealing contracts, long-term contracts, territorial exclusivity, and requirements contracts) that were tantamount to the same thing. Over time, the Court has become considerably more hospitable toward vertical integration, recognizing that vertical integration can represent an important means through which firms can minimize transaction costs. In the process, the Court rejected categorical prohibitions in favor of a more nuanced approach that evaluates the competitive impact of vertical integration and vertical contractual restraints on a case-by-case basis (Continental T.V., Inc. V. GTE Sylvania, Inc., 433 U.S. 36, 52-59 & n. 21 (1977)). The case for permitting last-mile networks to experiment with end user restric- tions also draws on economic considerations separate from congestion. For exam- ple, by allowing network owners to differentiate the services they offer, exclusivity can play a key role in mitigating the sources of market failure that require regulatory intervention in the first place. Indeed, some degree of discrimination and differen- tiation is inevitable in any industry characterized by large fixed costs. Furthermore, close analysis reveals that access requirements such as network neutrality are less justifiable and less likely to succeed in a world in which competition among last- mile providers is growing ever more robust, natural 