Twitter’s worldwide advertising revenues and overall share of the social ad sector are continuing to grow at a rapid pace, says a new report by eMarketer.

The micro-blogging network is pegged to earn $288.3 million in total ad revenues in 2012, up 106.7 percent on last year, and will see further gains over the next two years, with $807.5 million anticipated by 2014.

eMarketer anticipates 89.1 percent and 48.1 percent growth in global ad revenues for Twitter in 2013 and 2014 respectively, with Twitter ultimately commanding a 12.7 percent share of the total U.S. social network ad space.

While impressive, Twitter’s numbers pale in comparison to Facebook, which continues to dominate the sector, although its share is expected to shrink somewhat from 68.8 percent this year down to 63.5 percent in 2014.

Social games (7.4 percent) and LinkedIn (6.1 percent) are both expected to increase their share over the same period.

(Source: eMarketer.)