I don't believe that this is (despite stated intent) making Skype "open source". It would be more accurate to say that this work makes it possible to create an

I don't believe that this is (despite stated intent) making Skype "open source". It would be more accurate to say that this work makes it possible to create an open-source wrapper around a proprietary kernel. This wrapper could then be updated as times change to support different platforms, as long as the linkage to the kernel was compatible. This neatly steps around some legal problems because: 1) The wrapper itself is not encumbered (unless some patent issues applied) 2) Users with a legal copy of Skype on one platform can apply the wrapper themselves (though they cannot redistribute the result) You can even imagine distributing (via, say, github) a kit consisting of the wrapper and a tool that applies that wrapper to a user-supplied Skype binary. All legal as far as I know (IANAL etc.)