According to this study:

Gen Yers spend 12.2 hours online every week -- 28 percent longer than 27- to 40-year-old Gen Xers and almost twice as long as 51- to 61-year-old Older Boomers. Gen Yers are also much more likely to engage in Social Computing activities while online. For example, they are 50 percent more likely than Gen Xers to send instant messages, twice as likely to read blogs, and three times as likely to use social networking sites like MySpace.

"All generations adopt devices and Internet technologies, but younger consumers are Net natives who spend more time online than watching television," said Forrester Research Vice President and co-author of the report Ted Schadler. "Younger generations live online, reading blogs, downloading podcasts, checking prices before buying, and trading recommendations."