Twitter reaches 100 million active users

According to CEO Dick Costolo, there are about 100 million active users, despite 200 million registered accounts.

Growth in mobile usage is about 40 percent every quarter, an outstanding number, adds the CEO (via Reuters).

Notes Costolo, when asked if the service will go public soon:

We want to be able to remain independent, grow the business the way we want to, and not be beholden to public markets until we feel like we want to be.

Finally, the CEO says Twitter now has about 400 million unique visitors every month, up from 200 million on January 1st.