We encourage everyone to create videos using content from our games. We think it’s awesome you guys make all those fantastic walkthrough/playthrough/Let's Play movies, clips showing how to unlock certain achievements and video reviews of our games. We love seeing them all out there and in fact love watching them ourselves, so please feel free to publish them on YouTube and other video sharing websites. Please remember that the use of our content in your videos has to be non-commercial, meaning you can’t charge users to view your work nor can you sell or license it to others in exchange for any kind of payment.
You can, however, become a part of the YouTube partner program and monetize your videos with content from our games by participating in it or in similar partnership programs used by other video sharing sites.
Other than that, all we have to say is: create, have fun and be awesome!