The "convert-GIF-to-MP4" technique is the same technique that Twitter [1] and Imgur-competitior Giphy [2] uses.
[1] http://blog.embed.ly/post/89265229166/what-twitter-isnt-tell...
[2] http://www.reddit.com/r/IAmA/comments/2g0791/hey_reddit_were...
[1] http://blog.embed.ly/post/89265229166/what-twitter-isnt-tell...
[2] http://www.reddit.com/r/IAmA/comments/2g0791/hey_reddit_were...