-By Mike Shields, Mediaweek

In a major shift in strategy, YouTube will begin streaming long-form professionally produced content, starting with shows from CBS' library such as Star Trek and Beverly Hills 90210.

And unlike the majority of YouTube clips, this content will carry pre-roll, mid-roll and post-roll video ad spots.

Executives at the Google-owned property said the decision to break from the site's traditional emphasis on short video clips was based on demand from its own user base and the fact that long-form Web viewing has proven popular on other sites such as ABC.com. YouTube has been quietly exceeding its previous nine-minutes-or-less limit for video length by offering several documentaries and excerpts from political debates, and its users have responded positively, said officials.

"This is about giving the community what they want, said Jordan Hoffner, YouTube's director of content partnerships. "Plus, we're not blind to the growth of long form on other sites."

But with the move, YouTube is clearly headed to where the money is in online video. It's been well documented that Google has had trouble cashing in on the millions of user-generated clips the site streamed, while advertisers have gravitated to running spots within prime-time series via the CBS Audience Network, Hulu and other sites.

Hoffner wouldn't comment on whether YouTube's shift in strategy is based on the perceived financial success of the Hulus of the world. "I've never seen Hulu's books," he said. "This is just the right strategy for us. There is money in a lot of places. We're making good on our pledge to give advertisers choice." Hoffner added that YouTube would announce several additional content partners in the coming weeks.

Though CBS is not providing YouTube with current hits like CSI and Survivor, the Showtime series Dexter and Californication are included in the deal, as are classics like MacGyver and the daytime soap The Young and the Restless.