In order to get the significance of this blog one must first understand the concept of "easter eggs". Wikipedia describes them as "A virtual Easter egg is an intentional hidden message, in-joke or feature in an object such as a movie, book, CD, DVD, computer program, web page or video game. The term was coined – according to Warren Robinett – by Atari after they were pointed to the secret message left by Robinett in the game Adventure. ".
Easter eggs are in most computer games, software, operating systems, etc. There are entire websites dedicated to finding and exposting easter eggs. The easter egg that Yelp has put in there new iPhone app is mind blowing and it's social implications are endless. This takes the power of the people to a whole new level. Restaurants beware, if you get a bad review on Yelp, you're dead.
So check out this video on Monocle - Yelps hidden app (aka easter egg) underneath their iPhone app. It uses the camera in the iphone in combination with the GPS to determine your location then overlays that with reviews of the businesses in the immediate vicinity and direction you are pointing the camera. Like I said, mind blowing. Requires 3Gs iphone with latest software.
Check out the Mashable web site for more details and explanation of how to activate the easter egg.