In one embodiment, a client computer receives messages from a server computer over a computer network. The messages are displayed in the client computer based on preference settings that may be configured by end-users. This advantageously gives end-users some control over messages provided to them. In one embodiment, end-users configure the preference settings to specify the number of messages they can be shown within a period time, when to display messages relative to the loading of a web page, and/or where to display messages. Embodiments of the present invention may be used in a variety of applications including in the delivery of advertisements over the Internet.