I've been watching with great interest the recent move within Launchpad Translations (formerly known as Rosetta, the Translation Infrastructure used by Ubuntu and others) to enforce a licensing policy on translations contributed through the web-based translation tool. Basically, from the end of this month, translators will have to either agree to publish all their translations under a BSD license, or stop using Launchpad for translations.
In the past, translations were contributed under the same license as the project itself. The reason for this new direction is to be able to legally reuse translations across project and license boundaries. Up until now, showing translation suggestions from projects which had an incompatible license to the project being translated have been a rather fuzzy area.
I personally find it rather silly (or at least counterproductive to the goal of sharing knowledge) that resource-files such as PO files are covered by the same license as source code. What I do know is that we will start to see more and more cross-project reuse of translations, so thank you Launchpad folks for taking the first steps towards sorting out some of the legal issues!