Patent ID: 8359236

Claim:
A computer program product, encoded on a non-transitory computer-readable medium, comprising instructions operable to cause one or more computers of a system that includes an ad server to: provide references to one or more publishers, wherein each reference identifies a respective advertisement of multiple advertisements hosted on the ad server for multiple advertisers, the ad server being identified in each reference using a hostname that is specific to the advertiser of the respective advertisement, the references including a first reference that identifies a first advertisement for a first advertiser and that identifies the ad server using a first-advertiser-specific hostname, the references further including a second reference that identifies a second advertisement for a second advertiser and that identifies the ad server using a second-advertiser-specific hostname; receive, from a first client, a first request, the first request being a request for the first advertisement identified by the first reference; in response to the first request, determine from the first-advertiser-specific hostname in the first reference that the first request is associated with the first advertiser and send to the first client a first client cookie, the first client cookie including a unique first-advertiser-specific identifier, the identifier being specific to the first advertiser and to the first client; receive, from the first client, a second request, the second request being a request for the second advertisement identified by the second reference; in response to the second request, determine from the second-advertiser-specific hostname in the second reference that the second request is associated with the second advertiser and sending to the first client a second client cookie, the second client cookie including a unique second-advertiser-specific identifier, the identifier being specific to the second advertiser and to the first client; and record request data for a plurality of requests from a plurality of clients including the first client, the request data for each request comprising an advertiser-specific hostname identifying a particular respective advertiser and an advertiser-specific identifier specific to a particular respective client and the particular respective advertiser.