A method of establishing communication between an information source defined by a data processing system and a user accessing the information source with a data processing device via a communications network is described. The method comprises assigning a position in a queue to the user according to one or more rules; determining contact information relating to the user which enables an agent to contact the user; and establishing communication between an agent and the user at the head of the queue using the contact information. The method is characterized in that at least one rule relates to the use of the information source by the user, and that the method further comprises monitoring the interaction of the user with the information source, one or more of the rules using the monitored interaction to assign a position in the queue to the user, wherein the information source is a Web server and the user accesses the information source using a Web browser.