Modification of another quote I know: "Software freedom doesn't matter until it does"
With regards to Skype, for many years it continued to be a useful, P2P VoIP network, despite being proprietary software. At the start its encrypted connections attracted use by people who couldn't use phone networks for political reasons, among others. Before Microsoft bought Skype their were rumours of backdoors for so-called "lawful interception" purposes. When Microsoft bought Skype the network was restructured to route calls and messages through supernodes, which was believed to be for lawful interception purposes. In May 2013, German newspaper Heise wrote an article on an experiment they did where they posted a unique URL into Skype pointing to a server they controlled, which was probed by Microsoft's servers shortly after posting it into the Skype messenger. In other words, one or both of the Skype clients was sending the URLs to Microsoft, or Microsoft is using a MITM attack, or Skype is using keys created on the server-side by Microsoft. If Skype were free software, the community would be able to control its functions and remove surveillance features. Back in 2005 before we knew these surveillance features existed, it would be easy to ignore the speculative possibility that surveillance features could be introduced some time in the future. >From a free software perspective, if the software is not free then this possibility always exists and it is outside of our control. We want to be in control of our computing. Keep in mind that privacy is only one of the many reasons for advocating software freedom. Andrew.
