The Open Source Initiative (OSI) has certified it as an open-source license, but the Debian project judged version 1.1[3][4] to be incompatible with the DFSG.

The OSL is a copyleft license, with a termination clause triggered by filing a lawsuit alleging patent infringement.

This termination provision shall not apply for an action alleging patent infringement by combinations of the Original Work with other software or hardware.

[6]OSL explicitly states that its provisions cover derivative works even when they are distributed only through online applications: 5) External Deployment.

[10] It has been claimed that the OSL is intended to be legally stronger than the GPL (with the main difference "making the software available for use over the Internet requires making the source code available"[11] that is the same goal as the even newer GNU Affero General Public License (AGPL), that is compatible with GPLv3),[11] however, unlike the GPL, the OSL has never been tested in court and is not widely used.

"[12] If the FSF claim is true then the main difference between the GPL and OSL concerns possible restrictions on redistribution.