SA – Share Alike
Meaning: Modifications are permitted but only under the restriction that the modified works are licensed under the same licence as that of the original work when published.
Consequence and problem: In practice, the condition Share Alike has the effect of the licence being inherited. For adapted works, it is therefore effectively contagious in the event of publication—with no remedy. This is precisely the problem: If parts of a work licensed in this way are to be used in a new work (e.g., an illustration or a research article that is to be reprinted in an anthology), this new work would have to be published with the same licence. At first glance, this seems positive because it ensures that free content is created once again. In practice, however, this is often not possible, for example, because the new work is supposed to be published with a more open licence, because it is not published open access and thus without an open licence, or because different works are supposed to be reused whose licences are incompatible to one another.