Research from eMarketer has concluded that there by the end of 2009 there will be 18 million adults in the country that access the service at least once per month.

 

This is a sharp increase from figures produced by the research and analysis company in August, when it predicted there would be 12.1 million adult Twitter subscribers in the US this year. 

 

The revised figure represents 11.1 per cent of the country's internet users and in 2010, this number is expected to rise to 15.5 per cent.

 

"Since our earlier Twitter user estimates were published in April 2009, the number of Twitter.com visitors has risen sharply," said eMarketer senior analyst Paul Verna.

 

He added that "growing percentages" of internet users are signing up to the microblogging service, but warned that some abandon Twitter "after a short period of experimentation" and others chose to only use it infrequently.

 

Earlier this month, research by Rapleaf found that growth rates on Twitter are faster among more popular users, with those in the top 0.1 per cent seeing their average number of followers jump 275 per cent between March and the middle of June this year.