"Infectious" Open Source Software: Spreading Incentives or Promoting Resistance?

Some free or open source software infects other software with its licensing terms. Free or open source software is a copyright based licensing system. It typically allows modification and distribution on conditions such as source code availability, royalty-free use and other requirements. Some licenses require distribution of modifications under the same terms. A license is infectious when it has a strong scope for the modifications provision. The scope arises from a broad conception of software derivative works. A strong infectious ambit would apply itself to modified software, and to software intermixed or coupled with non-open-source software. Popular open source software, including the GNU/Linux operating system, uses a license with this feature. This Article assesses the efficacy of broad infectious license terms to determine their incentive effects for open source and proprietary software. The analysis doubts beneficial effects. Rather, on balance, such terms may produce incentives detrimental to interoperability and coexistence between open and proprietary code. As a result, open source licensing should precisely define infectious terms in order to support open source development without countervailing effects and misaligned incentives.