Had my first run in with instant personalization on rotten tomatoes today. It was really trippy to see myself get automatically ID by RT. Why is this necessary?

Had my first run in with instant personalization on rotten tomatoes today. It was really trippy to see myself get automatically ID by RT. Why is this necessary? I have never worried about facebook privacy, but this just crossed the line. I am going to turn it off, and see what happens.