noirExtreme

International Data Corporation (IDC) sees [US] residential VoIP subscriptions increasing from 3 million in 2005 to 27 million by 2009.

Source: eMarketer

"VoIP must prove that it is more than just a cheap replacement for [plain old telephone] service," said William Stofega, senior analyst for IDC's VoIP services research program, in a statement. "To do this, carriers will need to offer services that are compelling and affordable. "The winners will use the flexibility of IP to design services that differentiate themselves from their competitors," he continued.

Indeed: in just 18 months Skype grew from 0 to 35 million active users worldwide. How many users will Skype have in 2009? And what will be the VoIP ARPU by then do you think?