"Skype blocking" may become a more prevalent issue in the near future, especially in developing countries or in countries with government-run telecom companies such as China that have much more to lose. Blocking Skype isn't just about government control and protecting government-run carrier monopolies - it's fear of what Skype represents - "free speech" both in an economic sense (very low cost and in some cases "free") as well as in a socio-political sense - granting for example Chinese citizens anonymous, encrypted "free speech"- away from governement monitors and censors. This is true of other totalitarian regimes as well, but China in particular is unique due to its large population of technologically savvy and Internet connected people.

In many developing countries, free market economics are not their forte' especially in socialist or communist states. China for example has very stringent censorship controls on Internet access. Figuratively speaking, they've taken the popular Net Nanny or Websense software (corporate web filtering product) and deployed it at the ISP level to block access to sites they deem unacceptable.(I'm not sure exactly which software/hardware solutions they use for filtering.)

In any event, according to the Skype Forum, China Telekom has been blocking access to www.skype.com. Others in China piped in the thread that they weren't having problems accessing Skype's website, while another posted stated that as far as he knew, "Skype.com is blocked in Shanghai, the only place I know that skype.com isn't available in mainland." Regardless of which areas of China is being blocked, this is very disturbing news.

Fortunately, as of right now, according to the forum, they are only blocking access to Skype's English .com website, thus you can simply go to Skype's German site or another foreign Skype site to download Skype or setup a SkypeOut account. Assuming you can read the foreign language of course.

But what would happen if China decided one day to block all Skype packets? Technologically, I think this would be extremely difficult to block Skype, though not impossible. Skype-to-Skype P2P calls would be extremely difficult to block. It might be easier for China to block access to the SkypeOut since there are predetermined IP addresses for the SkypeOut service. Although, through the use of SuperNodes, I don't believe the Skype software client connects directly with Skype's servers, so even that might be difficult to block.

Several countries banned VoIP or VoIP gateways providing phone service a few years ago, so banning Skype wouldn't be without precedent. Several people have chosen to ignore the law and setup VoIP gateways anyway and have been arrested. It will be quite interesting to see if an entire country decides to ban or block Skype outright and the ensuing public furor.

Give me Skype or give me death! - The future Skype Battle Cry