Hi,
On Thu, Nov 12, 2009 at 11:39:51AM -0000, Sam Liddicott wrote:
My own short view is that those who buy such licenses support some development of free software, and that such a situation also restricts collaboration from those who don't want their contributions locked away like that.
I think it does not directly harm free software (only by effectively withholding deeper co-operation) but it may be seen to adjust the balance of the software eco-system affecting the decisions of others; i.e. such dual licenses present a "dangerous" middle-ground that is more attractive (making it all the more "dangerous").
As a harm, I think it is indirect - as a consequence of not directly supporting free software aims, and I think it can't be said to be more harmful that fully closed source although the pain may be felt more deeply through being inflicted by those who "are supposed to be friends".
I think there often is the harm to tell people they need to buy licenses if they want to use the software "commercially" (it's the case here and it was for Qt) or if they need support. This makes it look like Free Software could not be used commercially or for mission critical goals. I'd consider this a real threat as knowledge about Free Software still is pretty marginal in (higher levels of) enterprises.
I prefer to think of the author as offering a free-software version of an otherwise closed product and so consider it a net benefit, but perhaps it makes an only-free version less worth developing.
You also divide you user base (and such your potential developers).
Best wishes Michael