Common Public Attribution License

Common Public Attribution License

Author	Socialtext
Version	1.0
Publisher	Socialtext
Published	July, 2007
Free software	Yes[1]
OSI approved	Yes
GPL compatible	No[1]
Copyleft	Limited[2]
Linking from code with a different license	Yes

The Common Public Attribution License ("CPAL") is a free software license approved by the Open Source Initiative in 2007.^[3] Its purpose is to be a general license for software distributed over a network. It is based on the Mozilla Public License, but it adds a controversial attribution term paraphrased below:

[…] the Original Developer may include […] a requirement that each time an Executable and Source Code or a Larger Work is launched or initially run […] a prominent display of the Original Developer's Attribution Information […] must occur on the graphic user interface employed by the end user to access such Covered Code […]

The CPAL also adds the following section discussing "network use" which triggers copyleft provisions when running CPAL licensed code on a network service and this way closing the so called ASP loophole:

The term “External Deployment” means the use, distribution, or communication of the Original Code or Modifications in any way such that the Original Code or Modifications may be used by anyone other than You, whether those works are distributed or communicated to those persons or made available as an application intended for use over a network. As an express condition for the grants of license hereunder, You must treat any External Deployment by You of the Original Code or Modifications as a distribution under section 3.1 and make Source Code available under Section 3.2.

References

1. ^ ^{a b} "Mozilla Public License (MPL)". Various Licenses and Comments about Them. Free Software Foundation. http://www.gnu.org/licenses/license-list.html#MPL. Retrieved July 6, 2009. 
2. ^ Mozilla, MPL FAQ, http://www.mozilla.org/MPL/mpl-faq.html
3. ^ Jonathan Corbet (July 31, 2007). "Open-source badgeware". Linux Weekly News. http://lwn.net/Articles/243841/. 

External links

Free software portal

• CPAL version 1.0 text at the Open Source Initiative
• Free Software Foundation opinion on compatibility with GPL.