There has been much conjecture lately as to the size of the crowd at Beckapalooza. At the right are two photos I got from the website of AirPhotosLive.com. I went to Google Earth and used the Ruler tool to construct a rectangle overlay of the area.
The height=1,000ft
The length=2,500ft
Area=2,500,000
Area per person=20sqft (generous given that the four corners of this rectangle are sparsely populated)
125,000, give or take a vendor.