OXFORD, ENGLAND:  Twitter, the social Internet firm that tracks trends through individuals' updates of events around them, may eventually go to the stock market for funding if necessary, its co-founder Biz Stone said.

The three-year-old company was already making some revenue and would concentrate on that next year. "2010 is really going to be the revenue year. I don't know if we're going to be profitable, but we have plenty of time," Stone said on Monday.

In September, Twitter received a new round of funding from investors including mutual fund giant T. Rowe Price and private equity firm Insight Venture Partners, which analysts said set the stage for an eventual IPO or sale.

According to a person familiar with the matter, the new funds totalled $100 million, theoretically valuing the company at $1 billion.

Stone told reporters he did not want to sell the company but would explore alternatives to an initial public offering.

"The point is, we want to build our own company that will last for a long time. If an IPO's the way to do that, then sure. We don't have it checked off on the calendar yet," he said on the sidelines of an entrepreneurship workshop.

"We are definitely not interested in selling the company," he said. "If an IPO's the only thing, then sure. But if there is some other way then that would be great too. Maybe some other new way will emerge." he said at the Oxford University event.

Stone declined to give detail of how Twitter would introduce advertising next year on its site to its users, but hinted again it would be different from traditional forms of Internet advertising, which include display ads and sponsored search.

"Everyone's going to love it. It's going to be amazing," he said when asked about the dangers of its tens of millions of visitors taking exception to the move.

Twitter, which lets people send, or tweet, 140-character text messages to groups of "followers", is one of the world's fastest-growing social Internet companies.

Worldwide visitors to its site hit 44.5 million in June, up 15-fold from a year earlier, according to tracker comScore.