A method of recording allocation of resources in response to a request for a data item to be transmitted to a device in the network where the request comprises data indicative of one or more requested items. The device is typically a mobile device and the requested items can be key words making up a search request or can be web site names indicating web sites of interest to the user. In response to the request, data listings having items generating a match with the requested data item are identified and data indicative of a network location corresponding to the or each matched data item are retrieved. In addition data indicative of an amount of data and a resource allocation associated with the set of data accessible via the network location are retrieved and these data, together with a network subscription associated with device and the amount of data, are used to evaluate actual usage of network resources when accessing the set of data. If data are subsequently requested from the network location the evaluated actual usage is offset against the resource allocation so as to identify an amount of usage of network resources to be charged to the network subscription, and a record associated with said data listing is updated so as to log said resource allocation event.