Finally got to go to the top of this thing!
A little on what I've learned:
The sign was originally an advertisement for a real estate development, and read "Hollywoodland" in 1923. The sign was lit, and would flash "HOLLY," then "WOOD," then "LAND." Come 1949, The City of L.A. stepped in and decided the sign would represent the whole region of Hollywood, and removed "LAND" from the sign. Each letter is 45 feet tall, and the word stretches 350 feet long.
While doing my research, I came across a prank, and just couldn't resist posting a picture. In 1993 before the annual UCLA-USC football game, some students altered the sign to read "GO UCLA." It's also read "HOLLYWeed" and "GO NAVY."
http://en.wikipedia.org/wiki/Hollywood_Sign
http://www.hollywoodsign.org/the-history-of-the-sign/beacon-of-a-new-wave-mt-lee-and-the-birth-of-television/
http://robertkaplinsky.com/work/ucla-prank/