Internet audience duplication refers to the phenomenon of a single individual or group of individuals being counted multiple times in online audience measurement metrics. This can occur when the same person accesses a website or online content through different devices, such as a computer and a mobile phone, or when multiple people use the same device. It can also happen when a person visits the same website multiple times, either intentionally or unintentionally. This duplication of audience data can skew the accuracy of online audience measurements and can impact the effectiveness of online advertising and marketing strategies.