Toward Copyleft Equality for All
Bradley M. Kuhn's Blog ( bkuhn ) 2020-01-07
Summary:
I would not have imagined even two years ago that expansion of copyleft would become such an issue of interest in software freedom licensing. Historically and for good reason, addition of new forms of copyleft clauses has moved at a steady pace. The early 2000s brought network services clauses (such as that in the Affero GPL), which hinged primarily on requiring provision of source to network-remote users. Affero GPL implemented this via copyright-controlled permission of modification. These licenses began as experiments, and were not approved by some license certification authorities until many years later.
Even with the copyleft community's careful and considered growth, there have been surprising unintended consequences of copyleft licenses. The specific outcome of proprietary relicensing has spread widely and — for stronger copyleft licenses like Affero GPL — has become the more common usage of the license.
As the popularity of Open Source has grown, companies have searched for methods to combine traditional proprietary licensing business models with FOSS offerings. Proprietary relicensing, originally pioneered by MySQL AB (now part of Oracle by way of Sun), uses software freedom licenses to compel purchase of proprietary licenses for the same codebase. Companies accomplish this by assuring they collect all copyright control of a particular codebase, thus being its sole licensor, and offer the FOSS licenses as a loss-leader (often zero-cost) product. Non-commercial users generally are ignored, and commercial users often operate in fear of captious interpretations of the copyleft license. The remedy for their fear is a purchase of a separate proprietary license for the same codebase from the provider. Proprietary relicensing seems to have been the first mixed FOSS/proprietary business model in history.
The toxicity of this business model has only become apparent in hindsight. Initially, companies engaging in this business model did so somewhat benignly — often offering proprietary licenses only to customers who sought to combine the product with other proprietary software, or as supplemental income along with other consulting businesses. This business model (for some codebases), however, became so lucrative that some companies eventually focused exclusively on it. As a result, aggressive copyleft license overreading and inappropriate, unprincipled enforcement typically came from such companies. For most, the business model likely reached its crescendo when MongoDB began using the Affero GPL for this purpose. I was personally told by large companies at the time (late 2000s into early 2010s) that they'd listed Affero GPL as “Never Allowed Here” specifically because of shake-downs from MongoDB.
Copyleft itself is not a moral philosophy; rather, copyleft is a strategy that software freedom activists constructed to advance a particular set of policy goals. Specifically, software copyleft was designed to assure that all users received complete, corresponding source for all binaries, and that any modifications or improvements made anywhere in the chain of custody of the software were available in source form to downstream users. As orginially postulated, copyleft was a simple strategy to disarm proprietarization as an anti-software-freedom tactic.
The Corruption of Copyleft
Copyleft is a tool to achieve software freedom. Any tool can be fashioned into a weapon when wielded the wrong way. That's precisely what occurred with copyleft — and it happened early in copyleft's history, too. Before even the release of GPLv2, Aladdin Ghostscript used a copyleft via a proprietary relicensing model (which is sometimes confusingly called the “dual licensing” model). This business model initially presented as benign to software freedom activists; leaders declared the business model “barely legitimate”, when it rose to popularity