When you see information about software that you want to install, Ubuntu Software Center says whether the license is "Open source", "Proprietary", or "Unknown". It does not show more detail than that (e.g. GPLv2).
It should be helpful not only to make others understand the nature of free software, but also to distinguish free and open source software from software like (just an example) Google Earth, free for non commercial use.
This cannot be fixed in Ubuntu Software Center until Ubuntu packages themselves provide machine-readable information about their exact license. For one proposal to implement this, see <http://wiki.debian.org/Proposals/CopyrightFormat>.
See also <https://blueprints.launchpad.net/ubuntu/+spec/foundations-p-machine-readable-copyrights>.
Matthew do we want this?