Google+ has become the first of the major social networks in the world, which allowed the use of animated GIF-files in the profile photo [ http://bit.ly/ZRfBkB ]. It turns out that the story develops in a spiral, since moving pictures were fashionable as avatars on forums even 10-20 years ago, before the advent of the first social networks.
However, in those times, users had complete freedom. The forums rare people to sign this name. Mainly used pseudonyms. An animated avatar could be a joke or a funny picture. Now everything has changed. The use of pseudonyms is prohibited or require special authorization and profile picture must be present.
Some believe that Google makes a big mistake by allowing animated profiles of large size. Like, this is very annoying. Besides the social network Google+ pages, and so eat off a large amount of memory (150 MB each), so the extra animation them completely useless.