The lawsuit seeks the court to declare that the IAB's complaints concerning Gator's Companion Pop-up Banner Windows are unfounded.
The Redwood City, Calif.-based Gator is the maker of an ad software suite and behavioral marketing network.
According to the IAB, Gator's business practices "substantially infringe on the trademark, copyright and intellectual property rights of Web publishers and advertisers and do not adequately protect consumers from unauthorized content."
The IAB said the companion pop-up banner "obscures advertising and/or editorial content on Web sites through the use of specially designed pop-up windows and without the consent of Web sites or innocent third-party advertisers."
Gator in its suit said the ads are separate from the browser and don't modify the underlying browser window or the content of any Web page. In addition, the company said the consumer sees the site publishers' ad first and can choose which ad to click.