Last year at DebConf12 and the Paris mini-DebConf I mentioned some of the sophisticated techniques that the likes of Microsoft and Facebook are using to monitor their customers.
So when Skype was busted spying on the content of chat messages, it was no surprise for many people in the Debian community.
People are already rushing to find alternatives like XMPP and Jitsi. Debian 7 has been released just in time, with powerful features like TURN support that finally allow users to make free calls and chats with seamless NAT traversal. Sadly, Debian's built-in VoIP/RTC client, Empathy, only uses Google's TURN servers and not native Debian servers, but hopefully a solution will come soon, but it is easy enough to install Jitsi instead and configure it to use any of the free TURN server software on Debian.
It should be emphasized that Skype does not just spy on URLs in chat - it has simply been possible to detect this form of spying by detecting when the URL is accessed. Microsoft has taken out various patents for secretive monitoring of Internet phone calls and the analysis of speech patterns to detect both the content and emotions during a conversation. This allows them to get a very thorough analysis of the state of mind of every user at almost every moment and fine-tune the type of advertising and branding that is delivered to that person through conventional means and also through biased `news' reporting and other means.