Annette Ekin has an article on animated-GIFs-as-art-form worth checking out (said with extreme bias since Ryder Ripps and I were interviewed).
A point from the article:
Moody sees the "recent explosion" of GIFs going from the "underground" to catching on in popular culture and mainstream media, in outlets like NBC, as the function of a "historical accident." Because almost every browser can read GIFs, and the much-touted HTML5 web takeover is yet to happen, GIFs "are a universal medium by default." “This explosion was definitely not in the computer companies' usual planned obsolescence script," Moody says. The current browser readability, he says, is "like a gift given to people who are making stuff."
GIFs never really went away or went underground but a bare couple of years ago a Google exec was interviewed saying "I can't remember the last time I saw an animated GIF." His company prefers the kind of CSS-based animations you find on their main search page but you wouldn't have all the looping Seinfeld moments you see now if people hadn't had a more hands-on way of saving and passing around animations.