Paid search has come to YouTube. Users can pay to have their videos appear in a right hand sidebar called "Sponsored Videos" in the results of desired search terms.
It works pretty much exactly like AdWords. You bid on terms, set daily limits, etc. You only pay when someone clicks to watch.
Check out YouTube's YouTube video for more details:
Related Reading:
YouTube Adds Search to Embeddable Videos
Yellowbook and YouTube Enter Content Distribution Partnership
Link to a Point of Time Within a YouTube Video
