1) The images sliding around are done with photoshop, it's essentially a file the size of the video, with room for the text on the right side.
2) The text on the right side, the homer moving around and the countdown, are all done by the video editor, could be Premiere pro possibly.
3) All they've done is looked up high ranked 10-best articles and made it into a video taking advantage of it being video and not text content.
4) It's not entire episodes or entire scenes, but bits and pieces from certain ones, being no audio from video, and extremely short clips, with explained text information, I don't see why this would be a copyright violation. In no way are they taking away credit or revenue from the source, but created a new audience based on who was already interested in the content.
5) I also just realized that any media on the video, has a source it came from, which is probably another leverage to stay in the safe zone.