A method and a system for metering an advertisement having a message to be presented to a plurality of users of a communications network, wherein the metering is used to count the number of times the message is actually presented to one or more users. The method comprises the steps of embedding a code in the message; and detecting the embedded code to count the number of presentations. Preferably, the embedded code contains the client's identity so as to allow the server to identify the client who should pay for the advertisement, and a rate code for calculating an advertisement charge to the client. In order to prevent an unscrupulous host web server from manipulating the metering system, a challenge-response mechanism is used to ensure the metering system has not been reconnected through an alternate channel of the network. Furthermore, a click-through monitoring process is used to monitor whether the user actually clicks on the advertisement image to learn more about the advertised service or product.