The entirety of a web page, including clickthroughs, is cached at a location within a network intermediate a client requesting the page and the host web site for the page. Activation of a clickthrough, whether held in session cache on the client machine, or in the network cache causes a javascript program to generate an activation identifier giving the IP address of the machine activating the clickthrough and the time. This ID, together with an ID giving the IP address from which the web page originally hosting the clickthrough was retrieved is sent to the host web site, enabling them to prove their role in the establishment of communication between the client and the site targeted by the clickthrough. The generation of such identifiers also has applicability in the field of text messages, e.g. sent out by a publicity agent, and actuable to connect to a telephone number held by an enterprise within the telephone network. Activation of such a text message results in the return of suitable identifiers to the publicity agent to enable them to seek remuneration from the enterprise.