Internet voice pioneer Skype is working feverishly to bring its services back online after an outage left millions of users without the widely popular VoIP, video and instant messaging service.
"Some of you may have problems signing in to Skype -- we're investigating, and we're sorry for the disruption of your conversation," Skype wrote on its Twitter feed.
Later, Skype tweeted "Our engineers and site operations team are working non-stop to get things back to normal -- thanks for your continued patience."
Skype said most services were returning, but it could take much of the day for all users to be able to get back online.
"Skype is now gradually returning to normal -- we expect it may take several hours for everyone to be able to sign in again, however," Skype tweeted.
A Skype blog post said the company worked feverishly to bring services back online after the outage and provided insight into what may have taken the service down.
"Skype isn't a network like a conventional phone or IM network -- instead, it relies on millions of individual connections between computers and phones to keep things up and running," the company explained. "Some of these computers are what we call 'supernodes' -- they act a bit like phone directories for Skype. If you want to talk to someone, and your Skype app can't find them immediately (for example, because they're connecting from a different location or from a different device) your computer or phone will first try to find a supernode to figure out how to reach them.
"Under normal circumstances, there are a large number of supernodes available. Unfortunately, today, many of them were taken offline by a problem affecting some versions of Skype. As Skype relies on being able to maintain contact with supernodes, it may appear offline for some of you," Skype continued in the blog post.
The company added: "Our engineers are creating new 'mega-supernodes' as fast as they can, which should gradually return things to normal. This may take a few hours, and we sincerely apologize for the disruption to your conversations. Some features, like group video calling, may take longer to return to normal."
Skype, which launched in 2004, was long seen as a consumer-only Internet phone service, but quickly became a cheap and useful business tool. Earlier this year, Skype officially made its entrance into the IT channel with the launch of its first channel program.
Skype has made itself a household name for free and affordable domestic and international calling via the Internet. It's unclear how many calls were affected by Wednesday's Skype outage, but it is likely in the millions.
According to analyst and consulting firm Brockman & Company, by the end of the first half of 2010 Skype had been downloaded 560 million times; boasted 124 million active users each month; accumulated 8.1 million paying customers; and reported revenue of US$406 million. Additionally, Skype experienced 6.4 billion billing minutes during the first half of 2010, compared to 10.7 billion billing minutes for all of 2009; and facilitated 88.4 billion Skype-to-Skype minutes in the first six months of this year compared to 113 billion the entire year prior.