In an attempt to reconcile the competing interests of open source developers devoted to the freedoms of the GPL and putting corporate customers at ease, several sellers of open source software have adopted a dual licensing approach. Simply put, they offer their user base the option of choosing either a GPL option—for those who want to modify and support their own versions of the software—or a more conventional commercial license to allow its inclusion in a larger, proprietary software package.
So far, the open source database makers MySQL and Sleepycat, and the programming component maker Trolltech, have used this strategy successfully. In all three cases, each company controls all the copyrights to the work being distributed. Companies that are considering releasing proprietary software as an open source project should study this option, although it comes with the potential headache of having to manage licensees and potential conflicts with the GPL carefully.