Japan and South Korea have some of the most advanced broadband rates in the world, though each has taken a different approach to voice over Internet protocol, resulting in two very different adoption rates, according to Ovum.

By the second quarter of 2007, there were 15.3 million VoIP subscribers in Japan, representing 56.5% of broadband users and accounting for 28.2% of total voice subscriptions.

VoIP uptake in South Korea has been low, despite promotion of additional functions such as personalization and mobility. There were only 200,000 subscribers at the end of 2007, out of a total of 14.6 million home and work broadband subscribers, according to PointTopic.

The introduction of number portability in early 2008 leads Ovum to predict that 2008 will be the year VoIP catches on in South Korea. It expects VoIP to reach a 10% telephone market share by year-end.

"The different market development in the two countries implies that high broadband penetration is a necessary but not sufficient condition for the success of VoIP," said Ovum senior analyst Suran Seong. "A favorable regulatory framework, including interconnection arrangements and numbering reform, is also needed." [eMarketer]