Skype has more than 480 million user accounts - almost twice as many as Facebook - and the application comes bundled with more than 50 mobile phones and even the Sony PSP.
The funny thing is that Skype isn't even a financial success story, but it has long been a leader in Internet telephony.
The online auction powerhouse, eBay, bought Skype from entrepreneurs Niklas Zennstrom and Janus Friis for $US2.6 billion in 2005, but the agreement did not include a fundamental piece of peer-to-peer communications technology that drives the software.
eBay may have to shut down Skype due to this licensing dispute.
eBay has since been licensing the technology from the founders’ new company, Joltid, but the pair recently decided to revoke the licensing agreement. eBay is now trying to force Joltid to let it continue using the technology through legal battle in the English High Court of Justice.
Will you be able to function without skype?