Retail VoIP subscribers have doubled in the last nine months, according Point Topic. The numbers are even higher if you take into account softclient based systems like Skype. Largest growth was in Japan, where VoIP is bundled with the Yahoo/Softbank broadband offering. Here in North America, there are now over 2 million retail VoIP subscribers on cable. Not good news if you’re a virtual network operator, like Vonage.