Election day in the United States became the most tweeted about event in US political history on Tuesday with enthusiastic netizens firing off 20 million poll-related tweets, the social network said.
Americans flocked to Twitter and other platforms all day in a massive social media burst, posting photographic proof they had cast their ballots, cheering their favorite candidates along and analyzing the latest polls.

"With 20 million tweets, Election Day just became the most tweeted about event in US political history," Twitter announced on its official government and politics account @gov.

The number far surpassed the 10.3 million tweets sent during the first presidential debate in October -- an event the popular social network had at the time billed a record in US political history.

In an indication of the importance of social networks in the presidential race, both Barack Obama and Mitt Romney took to Twitter, Facebook and Reddit just hours ahead of polls closing to make last-ditch pushes for votes.

The campaigns have used social media extensively over the past few months to push people to vote and even try and beat the record 2008 turnout, when two-thirds of US voters cast a ballot.