My current cat named Boba shows very little interest unless my husband is playing a video game where the charactors are moving quickly acrossed the screen. She will jump up on the entertainment center and bat her paws at the screen. Other than that though, she won't even aknowledge it if I put YouTube videos of meowing cats on.
My mothers two cats on the other hand, they constantly appear to be literally watching tv with my dad. They sit right up on the edge of the couch and just stare at it. Sometimes their eyes get huge and bob back and forth like they are following whatever is moving. The dogs could care less though. They never show an ounce of interest.