Commercial Open Source Software
FOSS can be sold and often is, for example with support agreements including telephone and rapid patch response, or with services agreements to match configuration to an organization's process workflow. And there isn't anything wrong with that according to most FOSS licenses. Indeed, to this day the primary product of RedHat, the most commercially successful open source company ever, is the FOSS operating system Linux.
Commercial Open Source Software (COSS) often contains elements of FOSS, however it also limits availability of some enhanced functionality to closed proprietary software, thereby creating a potential path to the same old vendor lock-in, and so does not qualify as FOSS as a whole.
Dual-Licensed Software that is released under a proprietary license for administration reasons can still be FOSS if all of the software is also made available under license approved by the OSI.
COSS Software
Some examples of COSS are listed below. To include software on this list a link must be provided to a page describing the elements of closed software: unreleased proprietary code, with or without fees.
- ConcourseSuite (formerly Centric)
- Epiware
- OpenGroupware
- KnowledeTree
- Kolab - "These are collateral results of the following commercial activities: Uptodate, tested and supported packages for specific distributions can be ordered from the Kolab Konsortium."
- Magnolia
- MySQL
- project-open
- Scalix
- SpendidCRM
- SugarCRM
- Zimbra
