I didn't say anything about "quitting".
Just a significant number deciding it is time to back up their content.
And at the backbone level it is all charged by the Mbps for example http://www.level3.com/en/legal/ip-traffic-exchange-policy/ http://blog.streamingmedia.com/2014/02/transit-works-costs-i... So a jump in a significant portion of the user base from a few MB per user per day to several GB will be several thousand times more expensive for that day.