The standard banner ad size is no longer recommended, having been replaced by a 160 x 600 pixel "wide skyscraper." The other recommended sizes are a 300 x 250 pixel "medium rectangle," a 180 x 150 "rectangle," and a 728 x 90 "leader board."
Ad buyers can identify compliant sites by the display of the UAP Compliance Seal on a web site.
There are at least 23 major web sites, including those of AOL and MSN, that are already compliant with the UAP or will be in the next 18 months.