Stone, in an interview at Reuter's 2009 Technology Summit on Monday ( ), said of running advertising on the micro-blogging site but it will one day launch new paid tools and services.

Online pundits and bloggers have been closely eyeballing the increasingly popular Web site and criticizing . Many experts have been doling out dire warnings about the future of the microblogging site unless it comes up with a viable plan for making money sometime very soon.

Stone added that has hired a full-time product manager to analyze how it should develop paid services.

"It's becoming clear that advertising isn't a panacea in general and Twitter's execs apparently don't feel that the downsides of advertising would be outweighed by what revenue they could bring in," said Gordon Haff, an analyst at Illuminata. "That said, they haven't really said much about what their business model will be. They refer to tools. But client applications are already available for free from a number of companies. And some of the most obvious tools, such as search APIs, are already likewise available for free and it's always difficult to go from free to a charge."

Ultimately, Haff said, it may be wise for Twitter to steer clear of advertising. "But taking advertising off the plate leaves open the question of what will they, exactly, put in its stead," he added.