THE EFFECTIVENESS of Internet ad campaigns is under threat through excessive rotation of banner ads, claims Ajaz Ahmed of new media specialist AKQA. He is calling on Web media owners to adopt voluntary standards to restrict the number of ad banners rotated on their busiest pages - up to fifteen rotations a day in some cases, Ahmed claims. He argues that this makes it impossible for advertisers to be guaranteed high volumes of impressions during short-burst campaigns: 'Website owners may be guaranteeing volumes of impressions delivered on their sites over a long time scale, but the problem of over-rotation means that advertisers are taking pot luck on audience delivery on any particular day. In post-campaign analysis, we are finding we are not getting the required delivery of impressions within our timescale.'