More people are turning to the Web to watch television shows and movies, thanks to sites like YouTube and Apple's iTunes store. But there's an emerging breed of website that's letting people go beyond passively viewing video. A number of startups, including Jumpcut, Grouper, and Motionbox, are providing free software tools that let anyone mix video clips online and, in some cases, make movies even if they don't have content of their own.

Yahoo, based in Sunnyvale, CA, recently acquired Jumpcut after looking at the trajectory of Internet video, says Jason Zajac, general manager of social media at Yahoo. He says that more people are participating in online content creation than ever before, from publishing photos on Flickr to sharing bookmarked webpages on Delicious (both companies are owned by Yahoo). For Yahoo, Zajac says, Jumpcut had the best approach and technology to effectively stir the average person to put together personal movies.

Jumpcut has "enabled real-time video editing through the Web browser," says Mike Folgner, cofounder of the company. Using an advanced Flash-based application, people can preview changes while editing. "This real-time feedback mimics the desktop editing experience that people are used to," Folgner says.

Using the software is straightforward. You can upload your own video clips (each up to 100 megabytes in size) and then play around by changing their order, speeding up time, and adding special Flash effects that, for instance, make butterflies flutter across the screen. If the thought of starting a project with a blank slate seems daunting, there are plenty of clips and videos already available on Jumpcut, just waiting to be remixed. The preexisting clips are provided by other users and sponsors.

The corporate collaborations are part of Jumpcut's business model: in an effort to increase brand awareness, companies provide clips and offer prizes for the best user-edited short videos. Previous contests include remixing the trailer to the 2006 film A Scanner Darkly and putting together a short movie from a collection of New Line horror-film clips. A current promotion sponsored by the chip company Doritos has put out a call for a user-edited chip commercial that will air during the Super Bowl. So far, more than 300 commercials have been submitted, and some of them are surprisingly good, says Yahoo's Zajac.

The technology that's driving Jumpcut's site is based on the same Flash animation software that's responsible for a growing number of interactive websites. When you upload a file on Jumpcut, your original file is saved on the Jumpcut servers, and a copy is converted to a Flash format. You edit the Flash version in the browser, and as you do, explains Zajac, you're actually creating a set of Flash programming commands that are layered on top of the file. "You're not actually changing the [original] video file," he says. When you want to play the video, Jumpcut's software reads the commands and presents a video that appears to be edited. This approach enables relatively fast editing. It also has advantages when it comes to copyright control. If a clip on Jumpcut has been found to be used illegally, Zajac says, the original file will be deleted from the server, automatically removing it from all Jumpcut videos that used the clip.