source movies Apple is an Internet retailer and Netflix is a Web video rental service, but Hollywood treats them as if they were potential competitors to TV broadcasters. In the past two weeks, customers of iTunes and Netflix's streaming digital-movie service have noticed that a growing number of titles are disappearing from the sites or are scheduled to be removed. MacWorld wrote a story last week about how one of the site's contributors noticed that of the 15 films he bookmarked for future viewing at iTunes, nine were no longer available. Among the movies that vanished were Charlie Wilson's War, Eastern Promises, and Michael Clayton. "One would presume that there is some sort of licensing issue at stake here," wrote MacWorld's Dan Moren. "But it's a little odd that these movies just vanished into thin air. Man, it's like a bad horror movie." Yes, Dan, it is. And the culprit here is a system that for decades has pumped billions of dollars into the coffers of Hollywood studios and the television industry. What has happened is Apple and Netflix have crashed into windows. "Release windows" is the term used to describe periods of time a certain media is allowed to show a movie. Typically, a feature film is first released in theaters, then on DVD, followed by pay-per-view channels and finally on broadcast TV. Normally, release windows don't affect retailers or video-rental services after they've begun selling or renting films. Warner Bros. doesn't go into Best Buy and pull DVDs off the shelf when Comcast airs Casablanca. The corner Mom and Pop video store doesn't surrender copies of Gladiator to Universal Studios when the film appears on ABC. But Internet stores are being treated differently. What this means for iTunes and Netflix customers is that movies will pop in and out of the services. Spokesmen for Netflix and Apple confirmed that they pulled titles due to these licensing requirements. The big question many Apple and Netflix fans will have is why are Web stores being treated as if they were entertainment companies instead of merchants? The answer, of course, is because broadcasters say they are. You got to go back decades to understand how entrenched these release windows are in the film industry. The major movie studios were once afraid of television until they realized TV represented a big new revenue stream. CBS, parent company of CNET News, scored a major hit in 1959 by purchasing exclusive broadcast rights for The Wizard of Oz. The classic movie, starring Judy Garland, aired exclusively on the network for years. The cash really started to roll in with the rise of premium cable and pay-per-view channels. These outlets often pay big money for exclusive rights. If they say they don't want Apple, Netflix or any other Internet retailer selling or renting films inside their window then that's the way it is, according to two high-level studio execs. The situation comes down to basic dollars and cents. At this point, the revenue from TV deals dwarfs the money Netflix and iTunes generate. One recent study found that movie downloads make up only .06 percent of studio revenue, said Jan Sexton, an analyst with Adams Media Research. She said her firm estimates that the return is a little higher but is still tiny. Sexton said the studios can't be expected to dump these very lucrative release windows until the Internet sees much wider adoption. "The challenge for the studios is that the business is changing," Sexton said. "As these licensing deals come up for renewal it's possible that Hollywood will alter them to fit the new reality of digital distribution. Digital definitely has enormous amount of buzz right now and the studios understand that if you don't get control of the Internet consumers will rip the content and share it. "On the other hand they do have series of exploitation windows that keeps the profits coming in and helps the business stay viable," Sexton continued. "(The studios) aren't going to rush out to shut those windows and shift to digital distribution without carefully planning a strategy and finding some kind of reasonable return." The big media companies aren't sitting on their hands when it comes to Web. Several of the largest studios now offer catalog titles on Hulu, and Metro-Goldwyn Mayer recently posted a few films to YouTube. Warner Bros. has offered a digital copy of the hit Batman film The Dark Knight with every purchase of the movie on Blu-ray disc. One studio exec said Hollywood is trying to manage the transition to digital but is trying to do it in a way that doesn't kill their biggest money makers. "It wouldn't make any business sense to do it any other way," said the source. To be fair, he has a point. Look at the music industry. Atlantic Records just became the first label to see Internet sales equal that of CD sales and that benchmark took almost a decade to reach. It took that long even though it was easier 10 years ago to download music then to download the huge digital movie files now. As far as quality, the Web appears to be a long way from delivering true high-definition images. All this would indicate that it might be a while before digital film sales rival DVD sales. Hollywood will only be persuaded to give better terms to Internet stores when large number of consumers show them that they prefer this to traditional TV viewing.