The latest update to the YouTube app on Wii U allows for multiple new features. One we knew about was the ability to watch videos on your Gamepad. Another includes browsing videos on the Gamepad while one plays on the TV. I also just found out you can now sync your YouTube account with your Wii U and allow TV playlists and pairing. Have a video, or set of videos you want to watch on your TV, you can send them right to your Wii U via PC, tablet, or smart phone. You’ll just need to click the activation buttons on the app, head to the proper websites (YouTube.com/activate and YouTube.com/pair), input your given codes, and you are all set.
Here is some proof from a video I sent over from my iPad to my Wii U.