Gif
 

Most gifs are short and cover between 1 and 10 second's worth of video frames. Is this protected by fair use or some other doctrine?

I guess history of short gifs is related to size of gifs, longer gifs would be over consuming in the past, so that timing is standard and it will be till the end of world :)

Imagine 3-5mb gifs in dialup era

Fair use would probably cover such a short piece being used to illustrate what the full piece contains.

When viewing a 5 minute media, would you prefer a video, where you can go fast forward and rewind, or a gif where you could miss the most interesting part?
Gifs are short, because they are focused on a short moment. Either funny, scary, whatever...