Ever watch a YouTube video and check out the statistics to see how it ended up on your screen?
I did this recently with an amazing video taken on a scary looking bridge in Norway (Slartibartfast would be happy)
Looking further, what really got the graph moving was when it was first embedded in yahoo web mail. I interpret this as when it really started to spread between family & friends and traveled through the regions of Norway, Poland & Canada.
Despite the younger generation, social media, and views of some - email still has a long way to go before dying. Ever tried to set up any form of account for kids? Everything needs an e-mail address!
And don't underestimate where mobile is going. It hit Zynga fast, crippling a company that had it all.