However, I wouldn't have paid $580M for MySpace. I suspect that News Corp has misunderstood the loyalty that users will have for any particular social networking site. Social networking sites are all much of a muchness. There's always talk about people not wanting to throw away their carefully built "friends lists" on these sites. But, that tends to be from people that don't use them. Make no mistake. People can switch away from MySpace in an instant. And they will - as soon as the next cool thing comes along. I don't see much genuine value in MySpace.
And so to Skype. Is it really worth $3B? I think the answer is - it could be worth that much to someone. Their value is that, right now, they have many millions of regular users. There usually seems to be a few million logged on at any one time. Of course, they face the same (lack of) customer loyalty issues that any Internet service offering faces - there are no barriers to prevent users from switching to other providers. But that's OK. The thing you have to do here, is keep innovating with the software. There are some fabulous, valuable (paid) services that can be conceived of, innovating on a VoIP platform. Skype has only just scratched the surface. It's not hard to imagine ways in which Skype's future revenues could support a value well in excess of $3B, if the buyer is smart enough to exploit the opportunity.
I think there are two classes of potential buyer for Skype who would pay billions for the company. The first is a buyer that doesn't understand in a deep way what they're buying, and thinks that billions isn't too much based on some comparator or other e.g. dollar value per customer etc. The second class is buyers that are confident they can build on what Skype has already done - innovate new services, and do what's necessary to keep the call quality up.
All of which which means the list of buyers is potentailly quite long. It could include media companies (like News Corp), other Internet software/service companies (like Google or Yahoo), or telecomms companies (fixed line or mobile). If the investors can't sell the company, I suppose an IPO isn't out of the question. However, whether or not an IPO'ed Skype could sustain a near-term valuation above the low hundreds of millions on the public markets isn't clear.