Its part of my brand. Used everywhere possible... some exceptions...
2 forums that are private forums I am on, I use an animated MLP avatar.
Steam used to not let you use a custom picture, and I had chose the tank picture. Of course nowadays you can upload a picture, but I never did.
On Pinside, the picture did not work correctly (they use different frames) so I use Negative Polarity Ravage.
Twitter decided to force circle avatar frames, and so you can't use some images designed to be displayed as a square. So instead I use Ravage from Transformers: Battle Tactics.