Animated avatars, which appear below your name, were never banned. However, pictures in your signature area, the area that appears below any post you make, were restricted. These animations were getting wildly visual and the files sizes were getting huge, making it harder for people to enjoy the forum because they would have to wait for them to load up. Then, when they were loaded, the animations were getting vibrant and intricate. This could slow a persons computer as well.

So because of this, there is no animation in the signature area but the avatar can, since the file size for an avatar has a maximum file size and can only be 80X80.