A disclosed example apparatus includes means for storing a logged media impression for a media identifier representative of media accessed via the Internet, means for communicating to send a third-party device identifier or a user identifier corresponding to the user to a database proprietor when a user has not elected to not participate in third-party tracking corresponding to online activities, and receive user information from the database proprietor based on the third-party device identifier or the user identifier, and means for processing to log a demographic impression based on the media impression and the user information, and generate an impression report corresponding to the media based on the demographic impression.