Young TV viewers have increasingly been moving to online platforms for some time. Twenty-seven percent of U.S. online 18- to-24-year-olds now watch five or more hours per week online. In addition, 29% of viewers 18 to 24 watch between one and four hours; 17% watch under one hour, and 28% watch no video online. Heavy usage of online programming drops among older viewers according to Forrester Research results, which show that among 25- to-49-year-olds, 12% watch five or more hours; 18% watch between one and four hours; 20% view under one hour; and 50% watch no video online. Among older viewers -- 35- to-44-year-olds -- only 9% watch five or more hours per week.Overall, more than 60% of young TV viewers watch some programming online, with 22% of U.S. online adults watching at least some of their video entertainment on Netflix, and 17% from TV networks’ own Web sites.Forrester says there has been an overall 18% hike in online viewing in the U.S. between 2012 and 2010. These results came from data of more than 60,000 North American survey respondents in April and May 2012.Jim Nail, a media analyst at Forrester, writes: “This season’s surprisingly low ratings have motivated even the major networks to adjust to a future of time-shifted and multiplatform viewing -- one that challenges their grip on prime-time audiences."