Ever since YouTube functionality for the Wii U browser was disabled, I along with other Wii U owners have been displeased to say the least. Visit the YouTube community in Miiverse and you’ll notice the apparent outrage. There is, however, a temporary workaround to this problem: just select a video for viewing and add “_popup” at the end of the word “watch” in the video’s URL.
example: http://www.youtube.com/watch_popup?v=iXXS3kEKkpw
Tap “OK” …and voila! There should be YouTube goodness on your gamepad once again.