U-Haul's feeling deflated after a judge popped the rental company's lawsuit against WhenU's pop-up software. When consumers visit U-Haul, WhenU's software launches pop-ups for competitors. The software monitors a Web user's activity and when it finds a similar Web site, it automatically displays those sites in a pop-up window covering the user's original destination. U-Haul sued WhenU for trademark and copyright infringement but a federal judge dismissed the lawsuit since consumers have chosen to download the software.

Pop-ups always stir controversy. Sites such as Google and Alexa, promote software that automatically blocks pop-ups. And the U.S.-based Internet Advertising Bureau (IAB) invoked a cap on intrusive pop-ups for UK online media owners. But a recent study shows people are clicking through pop-ups, making pop-ups twice as effective as banner ads.