Pictures of PPT

While attending the National Retail Federation's Big Show in New York City, I noticed an interesting development at the sessions. In the sessions that Shop.org had programmed, every time a new slide came up, cameras came out and 10-20 people in the audience took a picture of the slide. It reminded me of the start of a SuperBowl, with camera flashes going off everywhere. Anyone have a theory on why people are doing this (sharing with their company, perhaps?) when most of the speakers did offer to send out a copy of the PPT.