"InfoTrends just published a survey showing that 8 billion photos were shared online in 2006" ~Adorama (May 22)

That's a lot of photos! I'd love to know how they come up with those numbers, especially since it says a lot of those photos are shared through email. It says, "3 billion images were shared via e-mail in the US in 2006". How do they know what you're sending in your email?

There is a claim that the main reason people take digital pictures is to share them. What do you think? What's the main reason you use a digital camera?