Methods and apparatus to determine impressions using distributed demographic information

METHODS AND APPARATUS TO DETERMINE IMPRESSIONS USING DISTRIBUTED DEMOGRAPHIC INFORMATION An apparatus comprises a communication interface to send a communication to a first client device in response to a first request from the first client device, the communication to cause the first client device to send a first identifier to a database proprietor in association with a cookie identifier of the first client device, the first identifier corresponding to media accessed by the first client device and a data structure to: log a first impression in association with the first identifier corresponding to the media accessed by the first client device; and log second impressions associated with the first identifier and corresponding to access to the media by second client devices, the second impressions logged in response to second requests from the second client devices. The apparatus further comprises a processor to generate a report based on (a) the first impression and corresponding first demographic information from the database proprietor, and (b) the second impressions and corresponding second demographic information from an audience measurement entity different from the database proprietor. 1 1 OI\O- A 1