The evidence of history, sociology, etc. indicates one thing which makes human beings a unique species is our love of telling stories.
One wag joked the first question ever asked by one language-using human to another was, "And then what happened?"
The trials and tribulations of the rich/famous/prominent make for better stories than the our own mundane lives, so (many) of us follow those stories. It's the same reason many of us read fiction books, or get invovled in cheering for sports teams, or go watch movies, or etc.
I fall into the book category. When I was a teenager, I had a HUGE crush on Donny Osmond, and read everything about him I could get my hands on. I outgrew that by the time I was 16 though. I have read a few biographies and autobiographies of celebrities and enjoyed a few of them. I don't really read celebrity gossip too much though, just watch it if it's part of a newscast or something.
Very good comparison. I feel the same way. I don't mind reading celebrity gossip once in a while, but I don't obsess over it and don't really care about their personal life.