Reporting from San Francisco — It's not what he said, it's what he didn't say.
Twitter Inc. Chief Executive Dick Costolo dismissed talk of Google Inc. buying his company for as much as $10 billion as "just a rumor." The comment came in answer to a question after an afternoon keynote address at the Mobile World Congress in Barcelona, Spain.
But when a question came up about a rumor that Facebook Inc. was in early talks with Twitter, Costolo declined to comment.
The exchange Monday could fuel the near-constant speculation that Twitter will eventually be bought. The possible combination of the two hottest social networking companies in Silicon Valley had tongues wagging Monday.
"Twitter would be a great acquisition for Facebook as both platforms march towards global ubiquity," Wedbush Securities analyst Lou Kerner said. "Facebook also wants to keep Twitter away from Google."
Facebook and Twitter have engaged in talks in the past, but nothing came of them. But recent rumors of arch-rival Google's ongoing interest in Twitter could have spurred a new round of talks between the social networks.
Facebook and Twitter, which are privately held companies, declined to comment. Facebook's market valuation is north of $50 billion after venture capital firm Kleiner Perkins Caufield & Byers said Monday that it had taken a $38-million stake.
Overall, the social media sector is in gold-rush mode. Online gaming company Zynga, maker of FarmVille and other successful games played on social networks, is reportedly talking to investors about raising $250 million in a deal that could value the 3-year-old start-up at $7 billion to $9 billion.
Costolo also said Monday that Twitter was making money, but he did not provide specifics about how Twitter's advertising initiatives were performing.
"Every time I have an interview, I am asked when we're going to make money. The short answer is we're already making money," he said.
Twitter's popularity continues to soar, with the service chalking up 130 million tweets a day. And Costolo said Twitter continues to change how people interact with one another and with the world around them, such as watching television programs in real time instead of recording them so they can chat about them on Twitter.
He said he wanted Twitter to be simpler to use and to work the same way on any device used to access the service.
"Users shouldn't have to think about how to use Twitter," Costolo said.