The number of people who went online while watching the Super Bowl increased 2 percent this year to 14 percent, according to Nielsen.

Time spent online for those multitaskers was up from 24 minutes last year to 29 minutes with much of that time spent on social networks.

Overall, Google and Facebook were the most visited sites while watching the game. Preliminary analysis of Nielsen's single-source measurement of Internet and TV, shows that 36 percent of simultaneous users visited Google and 34 percent visited Facebook. Facebook, which was visited during the game by 1 in 20 at-home Super Bowl viewers with Internet access, led the most -visited sites in terms of simultaneous time spent, averaging 19 minutes per user.

The growth of simultaneous use, particularly on sites such as Google and Facebook, indicates the growing importance of web interactivity in the television viewing experience, according to Nielsen.  This trend is expected to continue during the Winter Olympics and this summer's FIFA World Cup Soccer event.