Oh yeah. It's real.
Literally got this in my email box two seconds ago from @PonyNotes. I told him I would post it so hard. So this is me posting it so hard you don't even know.
From the email:
Just spotted this morning on the 101 freeway in Hollywood, is a brand new MLP:FiM billboard on the same site as the epic Bridlemaids billboard from the summer. This time, its Pinkie Pie in a scene from Ponygeist. Snapped this picture while driving by it this morning. It is brand new since the weekend, as it was other HUB advertising as recently as Friday Morning.