Why is Broadway called the great white way?

Answer 1

Because all the actors have dandruff!
Just kidding!

"Longacre Square had the first moving electric signs, and it was when the Times Building was erected in 1904 that Longacre Square ceased to exist. It was now known as Times Square. And because of the magnificent illumination of the Avenue and the Square, Broadway had been christened "The Great White Way"."
http://www.talkinbroadway.com/bway101/1.html

Answer 2

The stretch of Broadway Avenue in Manhattan known as the theatre district was called "The Great White Way" in 1902 by a newspaper editor because of millions of lights. Broadway was the first city avenue to be lit by electricity at the turn of the century.

Answer 3

All the bright lights on Broadway