Combining Licensing Models

Nothing obliges a licensor to release all of its software under an open source license. Even companies that are friendly to open source may decide that some of their software should be kept proprietary.

A good example of this is Jabber, Inc., which creates and distributes instant messaging software. Jabber comes in both client and server versions. The client versions of Jabber's software are open source and the server versions of Jabber's software are not.

Jabber on user desktops is fostered by the easy availability of open source client software, available for free download from the www.jabber.org website. Meanwhile, companies can build proprietary instant messaging applications tailored to their needs on top of Jabber's commercial server software available from www.jabber.com . This convenient division into .org and .com distributors of related software highlights the distinction between open source and proprietary software, but it also demonstrates that the two worlds can actually support and encourage each other.

Just as they may choose to license different components of their software separately, software distributors may also offer advanced versions of their open source products only under commercial licenses. Red Hat sells its Red Hat Applications, a collective work optimized for Linux, in that way. (See www.redhat.com .) These products are supported by a range of Red Hat Services, offered for a fee.

Open source licensing is a successful model, but it is not a religion. Alternatives are possible, and some of those alternatives are not entirely unfriendly to open source. Licensing creativity can allow contributors and distributors to make money while still encouraging, creating, and sharing open source software.