Twitter signups have soared since the launch of Apple’s iOS 5 operating system last week, with three times as many people now opting into the social network, the company said Tuesday night at the Web 2.0 conference in San Francisco.

Twitter CEO Dick Costolo revealed that the social network now serves 250 million tweets per day. The company has seen major growth in active users, with 30 percent of its 100 million users logging in every day.

Twitter’s iOS 5 integration likely is not only improving signups but it’s almost certainly getting users to tweet more. The ability to integrate your Twitter account with the iOS 5 is now a reality. Users can share pictures and tweets without having to log in to their Twitter account on multiple occasions. The iOS 5 makes it even easier to tweet from the iPad.

“We think that we can be on 2 billion devices around the world, and reach every person on the planet, and the way to do that is through simplifying,” said Costolo.

A new study released by SharesPost projects that Twitter’s revenue will grow substantially once its group of promoted products is fully operational. The report estimates that Twitter will reach $329 million in revenue by next year and half a billion dollars in annual revenue by 2013, surpassing the $1 billion benchmark in 2016.