The invention can enable monitoring of the display of content by a computer system. Moreover, the invention can enable monitoring of the displayed content to produce monitoring information from which conclusions may be deduced regarding the observation of the displayed content by an observer. The invention can also enable monitoring of the display at a content display site of content that is provided by a content provider site over a network to the content display site. Additionally, the invention can enable the expeditious provision of updated and/or tailored content over a network from a content provider site to a content display site so that the content provider's current and appropriately tailored content is always displayed at the content display site. Aspects of the invention related to transfer of content over a network are generally applicable to any type of network. However, it is contemplated that the invention can be particularly useful with a computer network, including private computer networks (e.g., America Online.TM.) and public computer networks (e.g., the Internet). In particular, the invention can be advantageously used with computer networks or portions of computer networks over which video and/or audio content are transferred from one network site to another network site for observation, such as the World Wide Web portion of the Internet.