Google Earth is interesting; it blacks out entire sections of top secret locations. Area 51 IS said to be a bit of a decoy though. There's another base to the northeast of Area 51 called S-4 where it is said the crashed UFO was reverse-engineered. It's one of the theories behind how our technology has developed so rapidly over the past 70 years.
Misdirection, my friend. Get all the conspiracy wackos thinking they're looking at the real thing, when the actual Area 51 is on the outskirts of New London, Connecticut. You think a secret base would be that easy to find?
OK, I made up that bit about Connecticut. Or did I? *shifty eyes*