Methods and apparatus to determine a unique audience for internet-based media

Abstract

Methods, apparatus, systems and articles of manufacture are disclosed to generate measures of unique audiences for Internet-based media. An example method disclosed herein includes a salt generator to generate a shared salt at a first database proprietor, a database proprietor interface to the shared salt to a second database proprietor, a Hyperloglog (HLL) generator to generate a first hash vector at the first database proprietor based on the shared salt and first user impression data associated with media, the first hash vector to obfuscate first personally identifiable information of first subscribers of the first database proprietor and an AME interface to send the first hash vector to a database containing a second hash vector, the second hash vector generated by the second database proprietor using second user impression data and the shared salt, the second hash vector to obfuscate second personally identifiable information of second subscribers of the second database proprietor, the first hash vector and the second hash vector to enable a third party to a deduplicate audience size corresponding to the first user impression data and the second user impression data.