The online is more popular than ever with US kids, as metrics maven Nielsen’s latest study notes a 63% jump in the amount of time kids spend online now compared to five years ago.

Nielsen found that the growth rate of young surfers has been surpassing the overall population on the internet, with some 16 million kids ages two to 11 comprising 9.5% all internet users. They’re spending more than 11 hours per month online, as compared to almost seven hours in May 2004, and it seems that boys spent roughly 7% more time online than girls, while girls viewed 9% more web pages than boys in May 2009.

The boy/girl split remains pretty even as the number of kids online has grown 18% since 2004. In fact, the growing number of kids online outpaces the overall growth of children in the US, where the number of kids under 14 is projected decrease by 1% from 2004 to 2010, according to the US Census Bureau.

Meanwhile, Nielsen also found that 26.3% of the online adult population (38.2 million), have kids 11 years old or younger in the household, up 7% from summer 2008, and online adults with kids under 12 were 1.7 times more likely to purchase a digital camcorder.

As for online video viewing, 5.1 million boys and 5.2 million girls tuned in online in May, while boys comprised 61% of video streams among children and 57% of time spent watching videos.

As for what they’re watching, Nielsen found the Pokémon site still ranked tops with boys and girls continue to flock to Barbie. Nearly 48% of video viewers on the Pokémon Web brand were boys between the ages of two and 11, while 38%of video

viewers Barbie.com were girls aged two to 11.