Jan 24, 2011 13:07 GMT  ·  By

Twitter's move to start monetizing the service and drive up revenues is paying off as 2010 was the first year in which Twitter managed to generate some meaningful revenue sum. And, according to a forecast from eMarketer, 2011 will be even better as Twitter is expected to triple its revenue, to reach 150 million.

"eMarketer expects Twitter to earn $150 million in revenues this year, the vast majority of which will come from the US. This represents a substantial increase over revenues of $45 million during 2010, the first year Twitter sold advertising," eMarketer writes.

However, the growth will not be sustained, as the report estimates a slowdown in 2012, when Twitter will generate $250 million.

Still, those are big figures for a company that's been around for years and is only now making money.

Twitter has over 200 million registered users at this point, though it has less active users. Still, well over 100 million users visit the site each month as well as millions more who may not be registered users.

That's one advantage Twitter has over Facebook, much of its content is publicly available and it regularly generates an influx of visitors interested in a particular subject.

However, Facebook has an estimated 600 million users and is now one of the most visited sites on the planet. The social network is rumored to have brought in $2 billion in 2010.

What's more, it's estimated that Facebook will generate $5 billion in revenue, mostly from advertising, this year.

Still, eMarketer believes that Twitter is in the position to take become the second place advertisers turn to in the social networking market which could result in significant sums for the 'information network.'

Twitter is expected to roll out a self-serving advertising product this year, enabling users to buy ads without going through a sales team. Opening Twitter to the much wider market of small advertisers would put it in a better position against Facebook or Google and is expected to generate a surge in revenue.