YouTube announced on their blog that they've started rewarding their most popular video uploaders by giving them a share of the advertising income that their videos generate:
Up until now there’s been a distinction between the content you create and the content created by YouTube's professional content partners. We want to start changing some of the perception here. Which is why we’re adding several of the most popular and prolific original content creators from the YouTube community to our partnership program. Now some of your favorite YouTube members, including Lonelygirl15, LisaNova, renetto, HappySlip, smosh, and valsartdiary, will begin to participate in the same revenue sharing and promotional opportunities that are available to YouTube's other partners. These include thousands of mid-sized to large content creators who range from video game companies to universities to production houses.
Initial user participants have been selected from the content creators that you have helped popularize by watching their videos and subscribing to their channels. Because they have built and sustained large, persistent audiences through the creation of engaging videos, their content has become attractive for advertisers, which has helped them earn the opportunity to participate on YouTube as a partner.
Participating user-partners will be treated as other content partners and will have the ability to control the monetization of the videos they create. Once they’ve selected a video to be monetized, we’ll place advertising adjacent to their content so participating user-partners can reap the rewards from their work.
So now that you’ve read this, you’re probably wondering, “How can I get in on the action?” This is only available to the initial participants. But if you create original content, have built and maintained an audience on YouTube, and think you might qualify for this program based on what’s above, you can express interest on our partnership lead form.