The key difference between the GPL, used in Linux and many other open-source projects, and the LGPL is that programs licensed under the latter can be used in proprietary programs.
In the past, OO.o has been dual-licensed under the SISSL and LGPL. Sun, however, decided to take SISSL off the licensing table to support the Open Source Initiatives goal of reducing the number of open-source licenses.
The reason for this is that the profusion of open-source licenses has made choosing licenses and avoiding conflicts between them difficult for developers and companies. Indeed, the problem has grown so large that there are now businesses, like Black Duck Software Inc. and Palamida Inc., which exist largely to track programming codes licensing issues.
What this mean for OO.o is that while its source code and executable programs up to and including OO.o 2 Beta 2 are licensed under both the LGPL and SISSL, from now on any modified code, and resulting programs, will be licensed exclusively under the LGPL.
For users and distributors, this change will make essentially no difference. Users can still use OO.o, and distributors can still bundle OO.o with Linux, PCs or software packages as they have in the past.
Developers are the only group that will be affected by the change. Besides switching over to the LGPL, Sun is insisting that anyone who contributes code to OO.o sign a JCA (Joint Copyright Assignment).
In the past, OO.o programmers had to sign a Copyright Assignment form with Sun before contributing code. This earlier agreement transferred all rights to the code to Sun. The JCA, however, gives both Sun and the contributor full rights to use, modify and redistribute the copyrighted work.