The news that leading UK Ad Agencies are avoiding advertising on P2P networks is a welcome long-term strategy, but many US Agencies and advertisers are yet to follow suit. The dilemma for advertisers and agencies alike is that file-sharing networks have massive reach and frequency and compare favourably in these terms with big established legitimate Internet properties. The fact that the likes of Kazaa have evaded closure for so long certainly makes a compelling case for the near-to-mid-term sustainability of the networks. However, all of these factors aside, it is the very advertising revenues which sustain the networks and any advertisers or agencies who opt to display advertising on them must accept their vital role in the process in their continued longevity. Agencies who persist on using file-sharing networks may find that the price they will pay is loosing the business of labels and movie studios.