OK so I've only noticed this recently, it pops up on random youtube clips and even on some videos not related to YT. The damn thing is everywhere ATM.
Here's 2 examples from different sources, you'll notice the empty box on the left had side of the pic.
Is it merely an overused effect that all the cool kids are doing right now?
Is it just in my imagination?
Are they sophons?
Anyone?
It's just a lens flare effect. What sort of videos are you watching? That doesn't look like Mat Armstrong.