Some people who come across Ardour and start reading about its "odd" license (the GPL, used by thousands or tens of thousands of software applications and libraries around the world) end up asking "what is with this whole open source/free software thing anyway?" or "why don't the Ardour developers just release Ardour like a normal commercial, proprietary program?".

It isn't a complete answer to this kind of question, but as exhibit 13.1(a) part 8, I offer you:

http://www.zdnet.com/users-petition-avid-to-sell-sibelius-music-software-arm-7000002271/

Summary: Avid buys Sibelius, which brings in a nice $18M or so a year, then appears to layoff all of its developers, mumbling about how they plan to integrate its development within their California development team. Sibelius users are extremely unhappy and attempt to convince Avid to sell the software.

Now, its true that had Sibelius been an open source program, it would probably have never been generating $18M of cash flow/revenue. But its also true that its users would not face this kind of situation. The company would probably not have been acquired, and if it had, its developers would have been free to continue working on their own fork after being laid off by the purchaser.

Rest assured, dear reader, that this is not a fate that can befall Ardour. There are other issues that the project faces, but this is possibly one of the most serious future usage threats to the user of any piece of software, and this cannot happen to Ardour. Because of the GPL. Good night and good luck to Sibelius development team and its users.