When it first launched, many people called Hulu a YouTube killer, but now the tables may have turned.

Hulu, which has enjoyed a modest amount of success because it sold out its limited ad inventory, appears to have changed the game over at YouTube. This despite the fact that comScore ranks Hulu far behind YouTube in terms of audience.

While YouTube remains the dominant online video destination, its devotion to short-form clips hasn't impressed advertisers who are looking for higher quality content to sponsor. But now YouTube, which has been scrambling to find a monetization model, is looking into long-form video.

In a recent Fortune article, YouTube laid out the thinking behind the long-form experiment. YouTube founders Chad Hurley and Steve Chen touted the success of "Harold Buttelman, Daredevil Stuntman," a one hour and 35 minute film that has attracted 1.1 million views since it was posted last July.

But for every "Harold Buttelman, Daredevil Stuntman" there are hundreds of shorter videos like "Tiger vs. Bear" that become instant hits and then fade away without any revenue being generated.

Earlier this month, YouTube launched a new program that would let producers of shorter clips like "Tiger vs. Bear" share in any ad revenue generated from their content. But so far, advertisers have been slow to take YouTube up on its offer to showcase home videos from around the globe. That reality, and the relative success of Hulu, may be behind YouTube's desire to experiment with longer videos, but unlike its competitors, the Google-owned property will have to bank on shows without brand name recognition. By contrast, Hulu features network television shows that come to the web with a built-in audience.