Rumors have been swirling that Twitter had noticed big brands using Twitter for customer support, general conversation and brand promotion and was planning on charging fees for commercial use.

Twitter, a micro-blogging service where users write short updates about what they’re doing, has attracted companies who want to create buzz online as well as those who want to see what customers are saying about them.

The source of the speculation was an interview with Twitter co-founder Biz Stone, which appeared on the Marketing magazine web site early on 10 February. Twitter Co-founder Biz Stone told Marketing: “We are noticing more companies using Twitter and individuals following them. We can identify ways to make this experience even more valuable and charge for commercial accounts.” He would not comment on the level of charges. Stone said it could also create revenue-generating features to tap into the way brands use Twitter as a hybrid marketing and customer-service tool.

Twitter denies reports that it will charge companies.

In a Twitter blog post, titled “Nothing to report just yet”, Stone noted that Twitter had been “thinking out loud” for over a year about the use of the service by commercial organizations, and how the offering could be improved.

“We hope to begin iterating on revenue products this year,” Stone said. ” However, it’s important to note that, whatever we come up with, 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.”

Stone has stated that there was no official announcement at present as the plans are still at a very early stage but plans are afoot to generate cash from value-add services.