Facebook may be the biggest social networking site in the world but the one thing that MySpace has always had as an advantage was page views. Users spent more time on MySpace and also did more things. Well, this isn't the case anymore according to a report by The Nielsen Co. The time users spent on Facebook grew seven times from April 2008 to the same month this year, putting it on the number one spot.

Facebook grew from 1.7 billion minutes last year to 13.9 billion in April 2009, a huge 700 percent increase. Meanwhile, MySpace saw a sharp decrease of 31 percent as users spent 5 billion minutes on the site in April 2009, falling far behind Facebook but still at number two with a comfortable lead. However, with Facebook already the biggest social network, with 200 million plus users, and now the one users spend most time on, things aren't looking very good for MySpace.

"We have seen some major growth in Facebook during the past year, and a subsequent decline in MySpace," said Jon Gibs, vice president of Nielsen's online media and agency insights. "Twitter has come on the scene in an explosive way, perhaps changing the outlook for the entire space. The one thing that is clear about social networking is that regardless of how fast a site is growing or how big it is, it can quickly fall out of favour with consumers. Remember Friendster? Remember when MySpace was an unbeatable force? Neither Facebook nor Twitter are immune."

Facebook's growth may be impressive, considering its size, but the biggest increase by far was Twitter's. There was little doubt that Twitter is growing at a lightning fast rate but now we have the numbers to back it up. The micro-blogging site saw a massive 3700 percent growth from just 7.8 million minutes to almost 300 million this year. The increase made it the fifth largest social network in the world, as regards the time spent by users on it.

"Let there be no doubt: Twitter has grown exponentially in the past few months with no small thanks to celebrity exposure," wrote David Martin, vice president of Primary Research at Nielsen Online, in a blog post. "People are signing up in droves, and Twitter's unique audience is up over 100% in March. But despite the hockey-stick growth chart, Twitter faces an uphill battle in making sure these flocks of new users are enticed to return to the nest."