Twitter suffered a backlash on Wall Street after its first set of results as a public company raised fears that its explosive growth of recent years is slowing down.
The micro-blogging website ended the quarter to December 31 with 241 million monthly users, a rise of 30% on a year earlier but down on some expectations.
The San Francisco-based company's addition of nine million new monthly users was also a slowdown from the previous three quarters, when it was adding an average of 16 million new accounts each quarter.
Its shares dipped by as much as 12% in after-hours trading on Wednesday night, even though its revenues more than doubled to a bigger-than-expected 243 million US dollars (£149 million) in the October to December quarter.
Losses of 511 million US dollars (£313.2 million) for the period compared with 8.7 million US dollars a year earlier.
Twitter shares began trading on Wall Street in November with an initial price of 26 US dollars and have more than doubled in value since then.
It has led to concerns that the stock is expensive compared with similar stocks such as Facebook and LinkedIn, although analysts continue to back Twitter's business model and long-term prospects.
Chief executive Dick Costolo said the site would only get better as it attempts to make it easier for people to start using the service.
He said: " Twitter finished a great year with our strongest financial quarter to date.
"We are the only platform that is public, real-time, conversational and widely distributed and I'm excited by the number of initiatives we have under way to further build upon the Twitter experience."
Twitter's public debut on the stock exchange was the most highly anticipated since that of Facebook in May 2012.
The company was launched seven years ago and last year named the UK as its biggest market outside America.
However one of the major challenges facing Twitter is to generate more revenues from outside America. While more than 75% of users are outside the US, just 26% of its revenue comes from abroad.
Dr Sotirios Paroutis, Warwick Business School associate professor of strategic management, said the market believed that Twitter needs to do better.
He said: "Inevitably, the market is evaluating Twitter not in isolation but in relation to Facebook, which posted record quarterly results a few days ago.
"In other words, while Twitter is doing well, it needs to do better - and faster - to keep its advertisers, users and investors interested - or as its chief executive admitted during the call to investors, 'we simply need to make Twitter a better Twitter'."
Patrick Salyer, chief executive of Gigya, a company that works with brands to help them understand their customers through social media, said the results show a change in the way people engage with "news-led issues".
He said: "While Twitter's revenue performance highlights the rather simplistic notion that social media sites are still quite popular, it also shows a fascinating shift in the public's interest in engaging with news-led issues.
"Twitter is arguably the most effective network for sharing news stories and having conversations with other users and celebrities around specific topics and this is a phenomenon that is fuelling user subscriptions to the site.
"Our own research shows that in Europe, 45% of social media users share content using Twitter with Facebook very narrowly ahead on 47%. The research, along with Twitter's growing global user base and revenues, demonstrates that the ways people now share content via social media is changing and it's getting more sophisticated.
"Social media is no longer just about sharing photos of your pets with a select group of friends, it's evolving into a truly global form of communication, with users determined to ensure their voice is heard."