Twitter Inc. co-founder Biz Stone said that the company has hired a product manager to develop accounts for businesses that would offer extra features but a fee would be charged, the Wall Street Journal reported.

Stone did not offer specific details as to when these accounts would be launched. Twitter has been growing exponentially, but the company didn't share on how it plans to monetize the micro-blogging site.

We think there will be opportunities to provide services to commercial entities that help them get even more value out of Twitter. If these services are valuable to companies, we think they may want to pay for them, Stone told Reuters.

Stone put out a statement clarifying his remarks: Twitter will remain free to use by everyone — individuals, companies, celebrities, etc. What we’re thinking about is adding value in places where we are already seeing traction, not imposing fees on existing services. We are still very early in the idea stage and we don’t have anything to share just yet despite a recent surge in speculation.”

The core functions of Twitter are going to remain free for individuals and companies, while the expanded service offerings are simply add ons, and that's what subscribers will pay.

In the Journal article about businesses which are already using Twitter to make money, Stone is quoted as saying he doesn't view that as competition for what his company will eventually do. We want to work with those companies that are already making an effort.