Six Easy Ways to Tell If That Viral Story Is a Hoax from Gizmodo. My favorite on the list was YouTube DataViewer, created by Amnesty International. It shows you the thumbnails and id number for a YT video, but more importantly, the date it was uploaded.
Some of the other tools are no-brainers (reverse image search), but Jeffrey’s EXIF Viewer is one I keep in my toolkit. In fact, I already had it slugged for another week, when we explore the creepy world of EXIF metadata. Can’t wait!