Well maybe not all of it but RedHerring has a good interview with Niklas Zennstr�m:

"Q: From revenue of $7 million in 2004 to more than $200 million---are you basing that increase solely on an increase in the number of subscribers?

A: The user base continues to grow, and the user base translates into people who are paying for existing services. But we also have recently added several new paying services.

A few of the offerings, like personalized Skype, [allow] our users to pay for digital phone services such as ring tones and avatars; the other service we just started to launch is a voice application service. We're signing up content providers to provide voice services---anything from phone translation to horoscope to stock market information to advise them. Our users are going to pay for them at a premium rate.

The other new service we'll be launching is pay-per-call. If you're a company, you want to have people call your call center---maybe you're selling products---you can have a link or a button and you could be anywhere on a web page or search results or directory. When a user clicks on that, the company is willing to pay for that click. It's similar to AdWords, but instead of coming to a home page, you're coming to a call center, you're talking to someone, and companies are willing to pay a premium for that.

These are new services, revenue-generating services. They will contribute to the revenues. The bulk of the revenue, however, next year will be from the SkypeOut service.

Q: Will you go beyond voice?

A: The core focus has always been voice, and communications around that. What we have today is online presence, text chatting, and voice, and we're adding video in the next release of Skype for Windows. We plan to focus on those services. What we'd rather do is hook in and integrate with other companies who are very good at what they're doing."