A system for the targeted contextual display of advertisements in a distributed computer network such as the Internet comprises management platforms (30,PP1,PP2) each having a sponsor site management unit (11) accessible to sponsors, a host site management unit (21) accessible to hosts and means for matching keywords, categories and/or parameters of the sponsor sites with those of the host sites for the targeted contextual display of advertising links from sponsor sites (10) on host sites (20). A shared server platform (40) is common to and interconnects the management platforms (30,PP1,PP2). Each management platform (30,PP1,PP2) is associated with its own sponsor sites (10) and its own host sites (20) and constitutes an autonomous system for management of the targeted contextual display of advertising links, that can be operated under the operator's own brand. The shared server platform (40) is arranged to enable the targeted contextual display of advertising links (Ad A, Ad B) from sponsor sites (10) on host sites (20) associated with different management platforms (30,PP1,PP2).