At least one non-transitory computer storage medium storing instructions that, when executed by one or more processing devices, cause the one or more processing devices to perform operations comprising:
- receiving, by an advertisement display server system, a first advertisement request that includes a first identification number that uniquely identifies a first ad space, from a first set of ad spaces, integrated in a web page to which a user navigates to using a first address, the first advertisement request being sent in response to the user navigating to the web page using the first address and instances of the first ad space being integrated in a first set of multiple, different web pages;
- in response to the first advertisement request, employing, by the advertisement display server system, the first identification number to identify, from among multiple, different ad space servers, a first ad space server that is assigned to select an advertisement for the first ad space identified by the first identification number and that is different than the advertisement display server system, the first ad space server being configured to select an advertisement for the first ad space identified by the first identification number each time a request including the first identification number that uniquely identifies the first ad space is received by the advertisement display server system regardless of which of the first set of multiple, different web pages is associated with the request;
- in response to identifying the first ad space server, accessing, by the advertisement display server system, first demographic data relevant to the first advertisement request and sending the first demographic data to the first ad space server when requesting the first ad space server to select an advertisement for the first ad space;
- receiving, by the advertisement display server system, a second advertisement request that includes a second identification number that uniquely identifies a second ad space, from a second set of ad spaces, integrated in the web page to which the user navigates to using the first address, the second advertisement request being sent in response to the user navigating to the web page using the first address and instances of the second ad space being integrated in a second set of multiple, different web pages;
- in response to the second advertisement request, employing, by the advertisement display server system, the second identification number to identify, from among the multiple, different ad space servers, a second ad space server that is assigned to select an advertisement for the second ad space identified by the second identification number and that is different than the advertisement display server system and the first ad space server, the second ad space server being configured to select an advertisement for the second ad space identified by the second identification number each time a request including the second identification number that uniquely identifies the second ad space is received by the advertisement display server system regardless of which of the second set of multiple, different web pages is associated with the request;
- in response to identifying the second ad space server, accessing, by the advertisement display server system, second demographic data relevant to the second advertisement request and sending the second demographic data to the second ad space server when requesting the second ad space server to select an advertisement for the second ad space;
- using the first ad space server to select a first advertisement for the first ad space integrated in the web page to which the user is requesting access;
- using the second ad space server to select a second advertisement for the second ad space integrated in the web page to which the user is requesting access;
- delivering the first advertisement for integration into the web page to which the user is requesting access;
- delivering the second advertisement for integration into the web page to which the user is requesting access;
- and
- balancing delivery of ads between the first set of ad spaces and the second set of ad spaces, the first set of ad spaces (i) being visited more frequently than the second set of ad spaces and (ii) being smaller than the second set of ad spaces.