January 18, 2008... What is causing the Skype surge?

Theories abound. Here's a brief collection ranked by probability.

1. Skype's deal with MySpace is bringing in multitudes of new users. Probability: just 10% because a. MySpace is a USA only phenomenon that represents but a fraction of Skype's user base, b. There is a surge at all times of the day worldwide and not just when you might expect MySpace users to be active, c. the Skype functionality that is added by Myspace does not necessarily result in more calling and more time online, though it may have resulted in a big increase in both downloads and Skype names. It's likely that only a fraction of these new Skype names have become regular or "real" Skype users.
2. Skype on mobile phones (a.k.a. Skype 3). Probability: 15%. Users of the Skype 3 service will display themselves and logged into Skype whenever their phones are turned on, so this naturally translates into an increase in "concurrent" users. On the other hand, Skype 3 users are not numerous and they are only in Europe, so it doesn't explain the surge elsewhere.
3. "Skype Pro" (and its predecessor "Skype Unlimited" in the USA), which is a bundle of Skype services introduced last year, was a successful first step in Skype's monetization process in that it did not permanently depress growth. Probability: 20%. Skype initiated a program of monetization in early 2007, replacing (in the USA) a free SkypeOUT promotional program. From the time of its introduction until September 2007, Skype growth was severely churned as users left Skype for other free VOIP services and were replaced by paying customers. As the process of natural selection was concluding, "normal" growth resumed, and in January 2008 (a full year after the process began), Skype began to make up lost ground.
4. Lots of new Skype subscriptions and/or Skype hardware in the proverbial Christmas stockings. Probability: 25% Why not?
5. People are starting to realize that Skype now offers a voice services package that, compared to other VOIP and "digital phone" carriers, imposes few compromises and costs extremely little. Probability: 30%. A USA Skype user can now, for example, buy "Skype Pro" for outgoing calls and "SkypeIN" for incoming calls for a grand total of just $60 per year after taxes. Comparable services from Verizon, Comcast, Time Warner and Vonage would cost $300 - $400 per year. The savings is a huge incentive. It has always been said that Skype's low pricing of SkypeOUT (especially international) appealed to the cost-conscious citizen. Now it seems that Skype's version of regular phone service (with "phones" to support it) appeals to the same demographic.