2009: The Year of Twitter and Facebook

Twitter, fuelled by smartphones and online bursts of 140 characters, soared to lofty heights over the past year while Facebook eclipsed MySpace to become the world's leading social network.

"Those are the big winners," said Jason Keath, a North Carolina-based social media consultant and founder of SocialFresh.com, an organiser of social media conferences. "Facebook more or less tripled their size this year."

"Twitter grew immensely," added Mr Keath. "I think they were somewhere around maybe two to four million users at the beginning of the year. Now they're near 40 million."

With 350 million members, "if Facebook was a country it would be the fourth most populous nation," said Scott Stanzel, a former deputy press secretary to president George W. Bush who has also worked for software giant Microsoft.

"Going back one year ago I don't think people would have thought Twitter would have had the influence it's had," added Mr Stanzel, who now runs Stanzel Communications, a Seattle-based public relations consulting firm that offers social media planning among its services.

"It was gaining popularity but it has really exploded this year and it's done so in a way that's become incredibly pervasive," he said.

Twitter has reportedly spurned takeover offers worth hundreds of millions of dollars from Google and Facebook and its influence as a communications and news-breaking tool has been validated in a number of ways over the past year.

In June, the State Department asked Twitter to delay scheduled maintenance on the service because it was being used by protestors angered by the results of Iran's disputed presidential election.

More recently, Google and Microsoft began integrating Twitter messages into their respective search engines, a new feature described as real-time search.

Rampant adoption of smartphones has much to do with Twitter's growth, according to Jack Levin, co-founder and chief executive officer of ImageShack, an online media hosting company which runs yfrog.com, a service for sharing images and video on Twitter.

"The explosion of smartphones in the US and many other countries has led to the success and ease of communication between people and Twitter is certainly in the middle of that," said Mr Levin.

"People obviously want to communicate and Twitter is really a communications platform," he said of the service which allows users to pepper one another with messages of 140 characters or less and provide links to the web.

"It's a hybrid between instant messenger and email," said Mr Levin.

Mr Levin's yfrog.com is one of the thousands of applications created for Twitter by outside software developers credited with fuelling the popularity of the microblogging service.

Facebook, which started the trend of opening up to outside creators of fun mini-programmes, was also quick to realise the appeal of being able to connect from anywhere at any time.