The popularity of Twitter in Japan is well known with the country being responsible for at least three of the most tweeted events in recent times. Now the company is planning to “aggressively” expand in the territory and attract more advertisers as local user growth exceeds the company’s global expansion, according to Twitter’s CEO Dick Costolo.

Bloomberg report that Costolo, who was speaking to reporters in Tokyo, said that the site will continue to invest and hire in Japan and will also add engineers to its ranks, but didn’t specify how many people would be hired and how much would be invested into this venture.

The microblogging site, which has over 140 million active users globally according to Costolo, is attempting to branch out to other markets to reduce its dependence on the U.S. for revenue. Currently, the U.S. accounts for 90 per cent of Twitter’s revenue – which amounted to $139.5 million in 2011 – but this dependence will drop to 83 per cent by 2014 according to Emarketer.

According to Semiocast, a social media site located in Paris, the U.S still accounts for the majority of Twitter users worldwide, accounting for over 107.7 million accounts,more than three times the size of its nearest rival Brazil, which has 33.3 million users. Japan is close by with 29.9 million, but the site is extremely popular in the country, making it the perfect place for Twitter to expand.