When I go to that page I see a Flash blocker icon and no animation, so no... it seems GIFs are not actually supported. And I'm going to be seeing a lot of broken tweets from now on.

I don't even know what it meant for GIFs to have been "unsupported" in the first place in the context of a browser that supports them natively, but I assume it has something to do with the above.

Yes, they are using a Flash player for the GIFs to prevent autoloading GIFs. Good idea as GIFs tend to be large. On http://myface.in we are starting the GIF-download on a hover, just like many other sites.

Also: record GIFs quickly in the browser at http://myface.in - to share on Twitter and elsewhere.