Barack Obama brought his sophisticated social media campaign to an emotional climax on Tuesday by proclaiming his victory on Twitter and Facebook just as TV networks called his re-election as US president.

San Francisco - A victorious message of “Four more years” accompanied by a picture of US president Barack Obama hugging his wife topped a collection of Year 2012 Twitter highlights released on Tuesday.

The nostalgic look back at the year by the popular one-to-many text messaging service recounted topics, news and trends that captured the attention of people around the world.

Obama's election night message was echoed 816 973 times by Twitter users in more than 200 counties, setting a new record for “retweets.”

“Within hours, that tweet simultaneously became the most retweeted of 2012, and the most retweeted ever,” Twitter said of the Obama message.

The second most retweeted message of the year was a loving farewell sent by Justin Bieber as a tribute to a six-year-old fan after she died from brain cancer. Bieber's simple, heartfelt message was retweeted 224 173 times.

Topics that prompted the “biggest conversations” at Twitter, as measured by spikes in message volume, included the US presidential election, the Summer Olympic Games, Superstorm Sandy and the death of singer Whitney Houston.

European and US football were also vibrant Twitter topics this year, along with the MTV Video Music Awards and the Japanese anime film “Summer Wars.”

“Notable Tweets” during the year included one sent by famed film director James Cameron from 10.9 kilometres beneath the surface of the Pacific Ocean in the Mariana Trench.

Details regarding Twitter trends for the year were available online at - Sapa-AFP