Animated a GIF's
GIF is a type of file. The GIF file type supports tranparency (which we don't really use it for much because it is lower quality than PNG) but it's really claim to fame is that it is capable of being animated. Yes, you could make a video. Video's require a player like quicktime, VLC or Media player to play them. They are also typically reasonably large files. GIF's on the other hand are a file that can be played in a browser, are small in size (which does make them lower quality) making them much eaier to share. They are perfect for easy viewing and going viral.