The Internet Movie Database, a subsidiary of Amazon.com, has begun showing more than 6,000 feature films and television shows on its site for free.

Col Needham, founder and managing director of IMDb.com, said in a statement that the move reflects IMDb's mission to be the world's most comprehensive source of movie, TV, and celebrity information, products, and services.

"We're excited to offer our users a simple online experience to watch full-length movies and TV episodes for free," he said. "Our goal is to show our users every movie and TV show on the Internet for free on IMDb.com."

But the distance between the present and that goal represents a revenue opportunity for Amazon.

"On title pages where IMDb does not have the content available for free, users can click on the Amazon Video On Demand button to rent or purchase the video from Amazon," an Amazon spokesperson said via e-mail. "It's great to offer customers choice. They can decide whether to watch an ad-supported movie or show on IMDb for free or rent or purchase a movie and show immediately from AVOD without commercials. So it's really the best of both worlds for TV and movie fans."

This is perhaps not the best news for Apple and its iTunes ecosystem, which faces an increasingly appealing and diverse set of film and video offerings from Amazon and IMDb.

YouTube may also be facing more capable competition, as least in terms of professionally produced content. In a bid to strengthen its position as an online film distribution service, IMDb is allowing filmmakers to upload their movies or TV shows to its site, provided there's a pre-existing IMDB page and the running time of the show is less than 45 minutes.

"The rules of distribution are changing quickly, and there's no better way to cultivate a worldwide audience than making your work available on IMDb.com," IMDb explains on its site.

It's not clear whether IMDb aspires to challenge YouTube as a source of user-created cat and accident videos. Asked whether IMDb might add more social features, an Amazon spokesperson said, "There are many opportunities ahead to enhance customer experiences on the site, but we have no information to share about future plans at this time."

Regardless, Amazon stands to benefit from pre-roll advertisements in IMDb's free content. CBS, Hulu.com, Sony Pictures Television, and more than 500 independent filmmakers are providing IMDb with free video content. Presumably, Amazon and IMDb get a cut of the ad revenue, but Amazon wouldn't discuss financial details.

It is Hulu's presence on IMDb that may trouble Google and YouTube the most, if anyone at Google shares Mark Cuban's pessimism about YouTube's ability to generate revenue. Hulu is backed by NBC Universal and News Corp., old media companies that would welcome YouTube's diminishment, particularly if it came at Hulu's gain.

In a blog post in June, Cuban, noted Internet billionaire and blogger, said he believes Hulu has a more workable business model than YouTube and that Hulu's success will drive up the cost of high-end content for YouTube.

"Hulu has one huge advantage over YouTube," Cuban wrote. "It has the right to sell advertising in and around every single video on its site."

The risk for Amazon is that it could help Hulu become a more popular movie destination than IMDb.