Abstract: Among other things, information is maintained that associates competitors with respective territories for which the competitors have rights that are to be exclusive relative to other competitors for items associated with the territories. A user can enter, through a user interface, an expression of interest that can be associated with one of the territories. In response to the expression of interest, a user is automatically enabled to interact with the competitor that has the exclusive right to the territory, without automatically enabling the user to interact with a competitor that does not have the exclusive right.