Originally Posted by LuigiHann
The official YTRickrollsYou version of the video is presumably with permission from the record company, which would mean there's licensing and royaltees involved.
Not so when somebody uploads their own, though.
The Official version is from Rick Astley TV. Whenever a RickRoll is caught by the video ID system, an Ad will appear next to the video. Whenever someone clicks on the ad, money goes into Rick Astleys Plaid Shirt Fund. It doesn't cost Youtube anything. When the rickroll part is less than 20 seconds, it probably wont get noticed by the Auto ID system.