A superstitial is a Web ad format developed by Unicast, which calls itself a rich media company. Superstitials combine Flash or other animation technology with Java programming to deliver video-like Web commercials.
A superstitial (trademarked by Unicast as SUPERSTITIAL, but industry usage is generally lower case), like an interstitial , runs in the dead time between Web pages. The superstitial is delivered with what Unicast calls a "polite" cache-and-play delivery system. Designed to load invisibly into the browser's cache (temporary storage area) within 60 seconds (while the user is viewing the Web site containing the ad), a superstitial doesn't appear until it is completely downloaded. The ad appears in a variably-sized pop-up window when something the user does (such as a mouse click) triggers a move to another Web page. If the user clicks off the site before a superstitial has finished loading, the ad doesn't play.
A user can click a superstitial ad off at any time, although they can't stop them from playing altogether. Superstitials are thought to increase stickiness (that is, they tend to hold the viewer's attention). According to Unicast, they lead to advertising terminology on the Internet rates of up to 40%, and an average of 7.5% compared to the .3% average of banner ads.