SAN FRANCISCO (Reuters) - Microblogging sensation Twitter has signed up more than 100 million users and hopes to snag hundreds of millions more in coming years by making the service easier and more accessible on mobile devices like cell phones.
At the company's first conference for Twitter developers on Wednesday, Chief Executive Officer Evan Williams said generating revenue was among the key priorities going forward -- a change of tone for a firm that had previously said it focused mainly on improving the user experience.
The comments come a day after Twitter rolled out a new advertising program dubbed "Promoted Tweets," its first attempt to make money from its service and a milestone on the path toward an initial public offering.
Twitter co-founder Biz Stone said Twitter now has roughly 105 million registered users. According to presentation slides, Twitter drew 180 million monthly unique visitors on its site, suggesting that Twitter may be more popular than previously believed. According to comScore, Twitter had 69.5 million unique visitors to its site in February.
Stone did not cite any specific timeframe for visitors to Twitter, introduced in 2006 and now used by politicians, corporations and others seeking to reach an audience growing several-fold annually.
A number of private companies have created specialized applications allowing Web surfers to access Twitter. Stone's slides showed that 75 percent of traffic for the service occurs outside of the Twitter.com site.
Twitter, which allows users to send short, 140-character text messages, or Tweets, to groups of so-called followers, is one of the Web's most popular social networking services, along with Facebook and LinkedIn.
Apart from growing revenue, Williams cited improvements to Twitter's infrastructure, its ease of use, and its ability to serve up Twitter messages by relevance, instead of simply in chronological order, as other key priorities.
The company provided official data about the usage of its site for the first time.
Privately held Twitter is backed by investors including Benchmark Capital and Spark Capital. Last year, the firm raised $100 million in a new funding round that valued it at $1 billion, according to a person familiar with the matter.
Stone said the San Francisco-based company now has 175 employees, compared with 25 employees at the beginning of 2009.
Reporting by Alexei Oreskovic and Edwin Chan, editing by Gerald E. McCormick