According to Nielsen, the United States alone watches about 1.4 billion hours of television per day, so 3 billion worldwide is probably not too far off: http://blog.nielsen.com/nielsenwire/nielsen-news/americans-w...

In fact, with India and China together having about 4 times as many TV households as the US, I bet the total is significantly higher than 3 billion hours, probably more like 10 or 20 billion (1/16 to 1/8 of humanity's time). http://www.nytimes.com/2007/02/11/business/yourmoney/11india... http://www.hollywoodreporter.com/hr/search/article_display.j...

1/5 of human life in the US is spent watching television. Probably around 5-10% of human life worldwide. Now that's cognitive surplus. Obligatory Clay Shirky link: http://www.shirky.com/herecomeseverybody/2008/04/looking-for...