Ethan Zuckerman was a designer and programmer for the early web-hosting service Tripod.com when a car company freaked out. The unspecified manufacturer had bought a banner ad on a page that celebrated anal sex, and was not too pleased at the association of its brand with sexual escapades. Thanks to work from Netscape and Opera, who were the first to add pop-up blockers into their products, the majority of web browsers now prevent sites from launching hundreds of ad windows.