It all started with Stake.com's "hyperactive" animated avatars and i bet it will end with their avatars too.
After the disabling of uploading animated avatars by Theymos, some campaign managers like Hhampuz even went ahead to encourage members to remove the animated avatars and stick with the static ones

But for stake.com, it was the opposite instead  

Explains where there as still loads of Stake.com animated avatars out there and i think it will only stop if the campaign stops or if Theymos just decided to disable even the current animated avatars.