Many of the most popular social networks have amped up their advertising options in recent months. Twitter has created a new platform for political advertisements as well as expanded Promoted Tweets and Facebook has launched a campaign to target small businesses as the next wave of advertisers. It’s no surprise that advertising from social networks is supposed to increase dramatically by 2013.

According to a report from eMarketer, social network ad revenues are estimated to hit $5.54 billion this year, with a little under half that amount coming from the U.S. market. It is estimated that a total of 8.8 percent of money spent on online advertising in the U.S. and 6.9 percent of money spent on online advertising worldwide will go to social networks this year. By 2013, social networks are expected to be responsible for 11.7 percent of online ad spending in the U.S. and 9.4 percent of spending worldwide. Revenue from outside of the U.S. is projected to hit almost $10 billion worldwide, and the U.S. is expected to pull in $4.81 billion.

Most of the money spent on advertising will likely be generated through Facebook advertising, with Twitter pulling in a much smaller share. This year, Twitter is expected to generate $140 million in ad revenue, which is projected to reach $400 million by 2013.

It’s not just Facebook and Twitter who shine in generating advertising revenue. This year, LinkedIn is expected to rake in $140.8 million in advertising — 3 percent of social network ad revenue worldwide.

It’s hard to say exactly how advertising will change in the next 2 years, but with growing options and people spending more time on social networks each year, the social media space seems like an advertising venue that has enormous room for growth.