Infonetics expectsVoIP revenue is poised to explode over the next three years to become a $120-billion business. In North America, it forecasts revenue to climb to $13.3-billion by 2009 from $2.6-billion in 2005, while sales in Europe and Asia will reach $12.7-billion and $12.9-billion respectively. The number of VoIP subscribers will double this year to 47 million. In North America, Vonage's market share has dropped to 27% from 34%.