Part of the answer comes a survey on the time spent online (done by The Media Audit, as quoted by BizReport, among a US audience).
"On average, American adults are now spending just under 4 hours each day online; that is an 81% increase over 2006 numbers, according to a new report from The Media Audit. Researchers have found that the Internet now accounts for more than 30% of a 'media day' for adults in the US."In other words: time spent online must have doubled since, let's say, 2005. And it makes up only 30% of a media day.