Twitter now has more than 200 million monthly active users, according to a tweet sent from the social network's official account on 18 December.

Tweet

The 200 million milestone has been reached in just under six-and-a-half years and comes nine months after the website announced that it had 140 million monthly users, which goes to show Twitter's growth is accelerating, although it remains someway behind Facebook's one billion active monthly users.

Twitter had 100 million monthly active users in September 2011 and half of those used the service every single day.

The announcements rounds off a hugely important year for Twitter, which saw it play a major role in world events, from the summer Olympics in London and President Obama's re-election, to be used more than ever by journalists in Egypt and Syria, reporting from the front line.

In June, Twitter CEO Dick Costolo said that the social network's users post more than 400 million tweets per day.

On 17 December, Twitter announced a partnership with Nielsen to create the Nielsen Twitter TV Rating, an industry-standard metric that is based entirely on data from tweets.

The new metric is intended to measure the engagement of TV shows by monitoring tweets about what's on television and to act as a companion to the Nielsen TV rating. 

Must Read:

2012: A Year On Twitter