On Facebook, more than 30.8million people "like" Barack Obama's page but only about 9.3 million are fans of Mitt Romney.

"If you're on Team Obama, let him know," says one post on the president's page shared more than 159000 times.

First Lady Michelle Obama has 8.5million Facebook fans - ahead of Romney's wife, Ann (381000).

On Twitter, @BarackObama has more than 20.8million followers.

Obama has been on the social network since March 2007 and his team often posts comments on his behalf. His own tweets are followed by the initials "bo".

Obama's account is the sixth-most followed in the world, according to Twopcharts, which tracks the most influential active Twitter users. The world's most followed Tweep is Lady Gaga, who has 30million followers.

@MittRomney arrived on Twitter two years after his rival and lags behind, with more than 1.4million followers. On Google+, Obama has more than 2.2million fans, almost twice as many as Romney's nearly 978000.

Obama has just under 240000 followers on his YouTube channel, which integrates campaign ads and filmed messages of support for the Obama team. Beyonce, for instance, appears in a video praising the First Lady.

Mitt Romney has a little less than 23700 fans. His YouTube page also includes campaign ads and other videos, including one depicting his "love story" with wife Ann.

On Pinterest - which allows users to post and share photos put together by theme - Obama boasts more than 34600 followers and Romney a mere 1700, but his wife Ann has drawn a following of more than 12400.

She has posted photos of herself cooking M&M cookies with her grandchildren or showing off a meatloaf - "one of Mitt's favorites". - Sapa-AFP