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.