To be fair, knowing someone's name is only one property of many when it comes to knowing them. It is technically possible — although perhaps unlikely — for someone to be more well-known than another even without having a recognizable name.

Zuckerberg probably is more well-known than Ed Sheeran. "Ed Sheeran", the name, may be more familiar, but what do typical people really know about the details of his life? Zuckerberg, on the other hand, had a movie made about him. At least everyone knows about Taylor Swift's dating life, if we want to compare to music celebrities.

Still, imagine Prince William or Prince Harry have to be most well-known. They've been chronicled since birth. Especially when you look past an Americentric view and turn to the world stage.