Subject: Re: Closed-source interoperability with the GPL From: "Brett Smith via RT" Date: Wed, October 31, 2007 9:04 am To: eion@bigfoot.com Eion, Thanks for sending those details about the Skype API. After reviewing them, I think you've already got the right idea: since Skype uses standard message-passing mechanisms on Windows and GNU/Linux systems, and its interaction with client programs is relatively high-level (i.e., there aren't entire data structures being passed between them), I see no reason to believe that your client software is derived from Skype. And if that's the case, there's no legal obstacle to writing a Skype client with GPLed software. Your plugin should be GPLed, of course, since it's derived from Pidgin, but the GPL does not prohibit this sort of arms'-length communication with proprietary software. I hope this provides the sort of guidance you were looking for. If you have other questions or concerns, please let me know. Best regards, -- Brett Smith Licensing Compliance Engineer, Free Software Foundation Please note that I am not an attorney. This is not legal advice.