This chapter address the issue of secondary liability in trademark law, specifically the ongoing uncertainty that still characterizes the application of the judicial doctrine of contributory trademark infringement. Scholars and courts in the United States have long discussed the standard to apply for finding contributory infringement. The debate intensified with the arrival of the Internet. In particular, several legal disputes claiming contributory trademark liability for intermediaries were filed in the years that followed the rise of the Internet. While this increase in disputes has led to a higher number of judicial decisions addressing contributory infringement, the precise boundaries for the application of the doctrine remain unclear. This chapter advocates for more clarity in this area. The chapter starts with a survey of the judicial development of the doctrine of contributory trademark infringement, first in the brick-and-mortar world and then as applied to the Internet. Based on this survey, the chapter notes that we still do not have clarity as to what represents sufficient “knowledge” and “control” to make an intermediary liable under the Inwood test, even though courts seem to have settled on a narrow interpretation of these concepts due to the concern that a broader interpretation would foreclose legitimate intermediaries’ activities. The chapter concludes that courts ultimately seem to follow a “we know it when we see it” approach in this area, based on an overall “benevolence standard” towards businesses that are primarily legitimate. Yet, this approach leaves too much uncertainty, and intermediaries and the service economy need clearer guidelines from the courts and, possibly, from the legislature.