The information box beside a youtube video. Usually referred to as the sidebar. The term was pioneered by Craig Benzine, better know as wheezywaiter, and was subsequently adopted by the popular vlogging siblings the Vlog Brothers.
wheezywaiter: "One more thing that's completely unrelated to this video: There's a new episode of Platoon of Power Squadron. It's a web series that I'm in... Link in the Doobly Doo."