This means, among other things, that
* You are free to use Glom without licensing costs, for as many users as you like. * You may view and modify the Glom source code, or you may pay someone else to do that. * Many organisations may offer support, so you are not dependent on one vendor. * If you modify the source code and distribute the resulting software, you should share the source modifications.
This does not mean that your Glom-based database systems must be open source, just as a document created with OpenOffice does not need to be open souce.
Glom uses many open source libraries from the GNOME project.