comcast logoComcast announced in a blog post today that it has surpassed the 10 million subscriber mark with its Xfinity Voice offering – a milestone that reminds us of the huge impact that cable voice services have had on the telecom market.

The company has more than tripled its voice subscriber numbers in just over five years. Back in August of 2007 Telecompetitor reported that Comcast had reached the three million subscriber mark.

The cable company’s strong voice service growth stands in sharp contrast with the voice service declines that traditional telecom service providers have seen over the same time period.

In today’s blog post, a Comcast Cable executive attributed Comcast’s success in the voice market – at least in part – to the company’s willingness to “reinvent” the telephone.

“We saw an opportunity to leverage Voice over Internet Protocol technology to create a converged experience with both our Xfinity TV and Xfinity Internet services,” the executive wrote. “Today Xfinity Voice integrates standard phone features consumers have come to rely on with new advanced features consumers have learned to enjoy with their wireless smartphones and tablets.”

She pointed to the example of the Xfinity Connect mobile app that enables customers to make free phone calls over WiFi using a smartphone or tablet, also noting that the company recently launched Skype on Xfinity and that the company continues to study the latest customer trends and technology.

“We’re currently evaluating and testing several new features that we may add to our roadmap as we continue to bring new communications innovations to our customers,” she said.

What’s surprising is that Comcast hasn’t been more negatively impacted by consumers’ shift toward wireless-only voice service. Perhaps some of the innovations that the company has made on the voice side have helped counteract that trend by keeping voice service relevant and interesting for customers.

Although not mentioned in the blog post, bundling undoubtedly has also contributed to the company’s success in selling voice service. Comcast’s VOIP service relies on the company’s broadband service, with both offerings sold as a service bundle. And I’m sure Comcast’s voice service also has benefitted from the overall shift away from DSL to higher-speed cable modem service.

The question now is whether bundling and service innovation will continue to fuel growth in voice services for cable companies like Comcast – or whether the wireless-only voice trend will eventually reverse that trend.

Comcast and several of the other cable companies are well positioned in either case. If customers want to go wireless-only, those companies also offer service bundles that substitute Verizon Wireless service for their own VOIP services.