
BARCELONA, Spain — Josh Silverman, the chief executive of Skype, the voice-over-Internet phone service, could tick off the names of mobile phone operators that block his company’s service. [...]
However, the barriers to Skype and similar Internet calling services, like Google Voice, are coming under increasing scrutiny as the Internet goes mobile. By 2013, the number of Internet-ready mobile phones will surpass the number of computers in the world for the first time, according to Gartner, a research firm.