Today April 1 is April Fools' Day! To entertain its viewers, Youtube redirected all of the featured videos on the homepage Rick Astley-Never Gonna Give You Up. Holy Rick Roll!
What is Rick Roll? Below is a simple yet very conclusive explanation by Col. Jack O'Neill
When what you think is a link to something you want to see actually directs you to a video of Rick Astley singing "Never Gonna Give You Up." This is common in the WoW community.