Aren't there any tools out there to make animated pngs yet? :/ they are superior race. GIF wins posterity though, I don't know if I like the webm stuff yet. HTML 5 video > than adobe tho that's for sure.
HTML5's ability to display webm / mp4 video really is the first step at animated images that the average user can post since GIF, and hopefully some how the user ease at making a GFY or webm/mp4 video will become easier over time. Maybe even have image upload sites make the new standard GFY/webm/mp4 looping videos instead of GIF.
Right now, you really can only make a PNG image sequence and create a video from that, then upload it, but with the 15 second limit you kinda are limited, and if you need more than 15 seconds then GIF still survives, for now.