Facebook might be the social media giant, but Twitter is playing the underdog pretty comfortably: according to new stats from eMarketer, Twitter is currently growing faster than Facebook in the US.

In 2010, Twitter was growing at a pace of 23.5 percent – lower than Facebook’s 38.6 percent growth that year. However, Twitter surged above Facebook in 2011, growing at a pace of 31.9 percent compared to Facebook’s significantly lower 13.4 percent.

eMarketer predicts that Twitter’s growth (as well as Facebook’s), will plateau following 2011, but Twitter’s growth will remain higher – four times higher – than Facebook’s through 2014.

Of course, eMarketer notes that the big gap in growth rates between the two networks is partly due to Twitter’s significantly smaller userbase to start with. At the end of 2011, Facebook had 133 million US users; Twitter had 24 million. There’s still plenty of room to grow for the little micro-blogging network that could, while the giant Facebook has pretty much saturated the US market.

By the end of 2014, eMarketer predicts that Twitter will reach 37.6 million by 2014.

Although these numbers are from the US only, they’re good indicators of how the two networks are growing. They’re both bound to plateau eventually, as more users sign up, but it’s clearly still the golden days of social media with the double-digit growth rates both Twitter and Facebook will enjoy for years to come.

(Growth arrow via Shutterstock)