Thank. Goodness. Starting next January, Google will crack down on sites with bothersome pop up adds by lowering their Google Search rank (page rank). The caveat is that Google will allow popups that actually contribute value to the website's content or the user's search to remain unaffected, as these pop-ups aren't considered pesky spam.
Image Source: By Created by Jeff Elie from images supplied by REACT Systems (Jeff Elie, Sydenham Publishing) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons