The Twitter symbol is displayed at the post where the stock is traded on the floor of the New York Stock Exchange in this Nov. 15, 2013 file photo. Reuters

Twitter (NYSE:TWTR), it turns out, is the microblogging service that could. The company has faced increasing doubts about its ability to grow beyond its core user base, but Twitter allayed those concerns reporting robust user growth in Q2, which included part of the World Cup.

The most anticipated figure -- monthly active users -- came in at 271 million, a 24 percent increase from the year prior and a healthy margin over Wall Street estimates. The company was helped by the World Cup, which set several Twitter records for sporting events in the second half of June.

The company is still losing money, but its reputation as the world's real-time watercooler remains intact. Shares jumped more than 28 percent in after-hours trading on the New York Stock Exchange.

"We are already the world's real-time information network," CEO Dick Costolo said. "We will postion ourselves to reach the largest audience in the world."

Twitter has a long way to go on that front. Facebook (NASDAQ:FB) is up to 1.44 billion monthly active users and even Yahoo (NASDAQ:YHOO) has 800 million global active users.

But Costolo made the case that Twitter is much bigger than its logged-in user base. Tweets are widely distributed and visitors can derive value from visiting and searching Twitter without ever logging in. For example, the World Cup match between Germany and Brazil generated 4.4 billion impressions on Twitter, but Costolo said another 2 billion impressions occured outside Twitter during the match.

Costolo said the experiences Twitter built around the World Cup gives him confidence that Twitter can better leverage the kind of big news events that have always fueled its growth. “Make no mistake, our total audience and reach represent a significant opportunity," he said.

Twitter has started to talk in terms of "audience," which sounds a lot more like a media company. Costolo said that its audience is 2-3 times greater than its active user base. Twitter makes money when users take actions with the ads, which means passive users aren't making Twitter money. "We are 100 percent focused on user experience today so we are not monetizing those audiences," Costolo said.

Twitter's logged-in audience appears to be in-demand from advertisers, many of which have built communications infrastructure on Twitter's platform and use paid advertising to drive it. Sales came in at $312 million, up 124 percent from the prior year. Twitter's ad business grew even faster, 129 percent to $277 million. The company also turned in a widening net loss of $145 million, compared to $42 million a year ago and $132 million in the prior quarter.

CFO Anthony Noto, the former Goldman banker who took Twitter public, said that Twitter's ad loads are low compared to its peers, meaning there's an opportunity to increase that over time.

Last quarter, Wall Street acted as if 25 percent user growth meant the sky was falling. Today, they're thrilled with 24 percent growth.

"We believe we are among the top-ten digital connected audiences in the world," Costolo said. "We have started to improve the experience for these unique visitors."