A system comprising: a plurality of advertisement servers (220, 230), each advertisement server operable to provide advertisement data defining advertisements and each advertisement server providing a different respective application programming interface, API, (222, 232) for communication therewith; and a user processing device, comprising: a script loader operable to download a respective interface script (414, 420) for each advertisement server; an advertisement request receiver operable to receive an advertisement request from an application on the user processing device; an advertisement server selector operable to select an advertisement server from the plurality of advertisement servers as a selected advertisement server from which to obtain advertisement data for the advertisement request; an advertisement translator operable to translate the advertisement request using the interface script for the selected advertisement server into a format required by the API of the selected advertisement server, to send the translated advertisement request to the selected advertisement server and further operable to translate advertisement data received from the selected advertisement server; and an advertisement renderer operable to render the translated advertisement data. a plurality of advertisement servers (220, 230), each advertisement server operable to provide advertisement data defining advertisements and each advertisement server providing a different respective application programming interface, API, (222, 232) for communication therewith; and a user processing device, comprising: a script loader operable to download a respective interface script (414, 420) for each advertisement server; an advertisement request receiver operable to receive an advertisement request from an application on the user processing device; an advertisement server selector operable to select an advertisement server from the plurality of advertisement servers as a selected advertisement server from which to obtain advertisement data for the advertisement request; an advertisement translator operable to translate the advertisement request using the interface script for the selected advertisement server into a format required by the API of the selected advertisement server, to send the translated advertisement request to the selected advertisement server and further operable to translate advertisement data received from the selected advertisement server; and an advertisement renderer operable to render the translated advertisement data. a script loader operable to download a respective interface script (414, 420) for each advertisement server; an advertisement request receiver operable to receive an advertisement request from an application on the user processing device; an advertisement server selector operable to select an advertisement server from the plurality of advertisement servers as a selected advertisement server from which to obtain advertisement data for the advertisement request; an advertisement translator operable to translate the advertisement request using the interface script for the selected advertisement server into a format required by the API of the selected advertisement server, to send the translated advertisement request to the selected advertisement server and further operable to translate advertisement data received from the selected advertisement server; and an advertisement renderer operable to render the translated advertisement data.