July 20–24, 2015
Portland, OR

When copyleft business models go bad ... and how Kallithea's community recovered

Bradley Kuhn (Software Freedom Conservancy)
10:00am–10:40am Friday, 07/24/2015
Collaboration E147/148
Average rating: ****.
(4.00, 1 rating)
Slides:   external link

Prerequisite Knowledge

Those with a basic understanding of typical software packaging details of a web application (including both Python and JavaScript), and who also have a cursory understanding of typical copyleft requirements will undoubtedly achieve the maximum benefit available from this talk. However, the talk remains accessible to a non-technical audience who simply has an interest and merely a passing familiarity in Free Software licensing issues and/or software packaging and release.


Kallithea is a self-hosted source code management system that supports both Git and Mercurial and includes most features found in similar systems (such as line-by-line patch review and commenting, online code editing, and a built-in push/pull server). This talk tells Kallithea’s interesting history.

Kallithea began in a rather unusual manner. Namely, its roots originate from a unique GPL violation and subsequent enforcement action. Typically, copyleft enforcement employs copyright infringement actions to compel license violators to follow specific policy goals: guaranteeing the rights of developers and users to copy, share, modify and redistribute the original software. While such traditional enforcement is often undeniably necessary, novel approaches to such violations are sometimes possible in certain situations. Kallithea’s creation provides an excellent case study of a unique approach to GPL enforcement and compliance, which yielded excellent community results. In short, Kallithea exists thanks to enforcement efforts by Software Freedom Conservancy whereby, rather than fighting the violator in court, Conservancy instead fostered and provides resources and assistance to a vetted GPL-compliant fork of an otherwise GPL-violating codebase.

This talk discusses which scenarios make this remedy optimal and explains the lessons learned. The talk also includes useful recommendations for proper GPL compliance when building online applications that integrate JavaScript with another server-side language framework. Release engineers and licensing wonks will (in particular) find this talk compelling, as it gives clear examples why license-compliant software releases require expertise from both those specialties.

Photo of Bradley Kuhn

Bradley Kuhn

Software Freedom Conservancy

Bradley M. Kuhn is the president and distinguished technologist at Software Freedom Conservancy, on the board of directors of the Free Software Foundation, and editor-in-chief of copyleft.org. Kuhn began his work in the software freedom movement as a volunteer in 1992, when he became an early adopter of the GNU/Linux operating system, and began contributing to various Free Software projects. He worked during the 1990s as a system administrator and software developer for various companies, and taught AP computer science at Walnut Hills High School in Cincinnati. Kuhn’s non-profit career began in 2000, when he was hired by the FSF. As FSF’s executive director from 2001–2005, Kuhn led FSF’s GPL enforcement, launched its Associate Member program, and invented the Affero GPL. Kuhn was appointed president of Software Freedom Conservancy in April 2006, was Conservancy’s primary volunteer from 2006–2010, and has been a full-time staffer since early 2011. Kuhn holds a summa cum laude B.S. in computer science from Loyola University in Maryland, and an M.S. in computer science from the University of Cincinnati. Kuhn’s Master’s thesis (an excerpt from which won the Damien Conway Award for Best Technical Paper at this conference in 2000) discussed methods for dynamic interoperability of Free Software programming languages. Kuhn received an O’Reilly Open Source Award in 2012, in recognition for his lifelong policy work on copyleft licensing. Kuhn has a blog, is on pump.io and co-hosts the audcast, Free as in Freedom.