Let's say we have a company and we release our project under LGPL && GPLv3, as you know the only thing here is about contribution. People commit bug-fixes/features to the project, it's fine and we are GPL fans.
Basically company makes money by this project. So what about contributors ? I know they commit code and software get better and it is actual repay to them, But how we can get contributors assign copyright for copyright holder?
Best Answer
In general, when an open source projects receives contributions from others because implicitly the contributor in contributing with the same license as that of project. This is true for most open source licenses single or dual. In this situation whether copyright of incremental work lies with project owner or the external contributor, everyone still has access to code.
However, the real question is what if the project has two licenses one open source and commercial? This is a problem because if an external contributor submits a patch that patch is not automatically ok that same patch gets redistributed to your customer automatically.
However, there are many successful projects, such as QT and MySQL, which have been available as open source as well as for commercial purposes. Read this: http://www.dina.kvl.dk/~abraham/rants/license.html
For example, what MySQL does is that it has what is called Sun Contributing License. Read this, http://forge.mysql.com/wiki/ContributingFAQ which says,
Sameway, QT also makes it clear that
Read this: http://qt-project.org/legal.html
Of course, there is a possibility that given this condition, some people may not contribute back. However, that's only fair. But both these projects goes at great depth why contributor still gets benefited by contributing back.