Magazine publisher Conde Nast and web video platform Brightcove on Monday inked a deal to bring ad-supported online video to many of the publisher’s magazine sites, including Wired.com, Parade.com, and Self.com.

Traditional publishers, who as a group have been in a downward ad-revenue spiral for almost a decade, are seeking ways to create new revenue opportunities. Many are now turning to the prospect of ads in online videos.

“You are going to see more and more deals like this as media companies like Conde Nast, who own content that translates easily into video but don’t have the technical expertise, looking to companies like Brightcove,” said David Hallerman, an analyst with eMarketer.

But the jury is still out on the effectiveness of online video as a magnet for ad revenue. eMarketer recently lowered its projections for the market.

Ad spending on online video has been locked in the low single digits as a percentage of the overall expenditure on Internet advertising, according to eMarketer.

“But it is growing rapidly albeit from a small base, and companies are grasping to get some share of the ad dollars online video is generating,” Mr. Hallerman said.

U.S. spending on online video will grow 56 percent in 2008 to $505 million, but it will continue to trail almost every other category of online ad spending, including search, email, and classifieds, according to eMarketer. (see TechSpin: The Good News About Online Ads)

Under the terms of the deal, Conde Nast will use Cambridge, Massachusetts-based Brightcove’s video service to publish, manage, distribute, and insert ads into its online video.