Most companies are looking for more customers but VoIP Skype has more reason than most. The company is hoping that a larger user-base will prevent telecoms companies and regulators blocking the service.

An experience in Brazil makes a good example, said James Bilefield, general manager of Skype in Europe. About a year ago, one of the largest telecom operators in Brazil blocked Skype. The reaction from Skype users was so strong that after a week, the operator relented. "The community has the power to change things," he said.

Some operators, particularly the incumbents, may seek to block Skype because Skype's low-cost voice service can steal market share from them and thus eat into their most significant source of revenue.

Incumbent operators speaking at the VON Europe conference didn't hide the fact that the VOIP players are a threat.

"Our existing cash flow is being challenged," said Joacim Damgard, vice president for broadband and fixed services at TeliaSonera.

With the introduction of the most recent version of Skype came news that the application does a better job of hiding its traffic on networks, making it harder for service providers or third party applications to block it. While Bilefield couldn't explain how the application does that, he did say that Skype has a mission to make sure that customers can use the software.

"Our goal is that consumers who want to use it should be able to," Bilefield said. "They shouldn't have anything in their way."

If the issue of blocking Skype gets heated, Skype thinks that regulators will be on its side. "Overall, regulators want to provide choice. Skype does that," he said.

Mobile operators have most recently begun to ban VoIP services. Last week, T-Mobile in the UK said that subscribers to a new data card service are forbidden to use VoIP services. Bilefield said that some operators have chosen to work with Skype because their customers want the service. E-Plus Mobilfunk in Germany and the third-generation network operator 3 are two companies that have made Skype offerings to their customers.

In the near future, some mobile operators may find it harder to challenge Skype. Skype has been working on creating a client that is compatible with Symbian, the operating system from Symbian, used in smart phones manufactured by Nokia Corp. and Sony Ericsson Mobile Communications. A Skype client is already available to users of phones running Microsoft's Windows Mobile OS.