Compatibility of Liberal Licenses

The compatibility of a license with other licenses is important for licensed materials which might be combined with other materials licensed under a different license and the compatibility is even crucial for works which are meant to be combined with other materials such as software libraries.

Read here about umbrella licensing, compatibility, also with other licenses

In general the Liberal Licenses provide a great compatibility, but in detail the compatibility depends on the license choosen. What means compatibility in terms of licensing? You might wish to alter a licensed material, but maybe you want to use a different license for the altered material. You might wish to combine a licensed material with other materials licensed under a different license to a larger work or you simply add it to a collection. Liberal Licenses differ between these cases, even if in practice the difference is often not so clear. Moreover, the assessment if a licensed material became a part of a larger work or a bare collection or is just an altered material, depends on the respective governing copyright laws and possibly on judgments.

As a rule of thumb: If you just link from your own work to a licensed material or you just add materials which can be considered reasonably as self-contained, reusable components to a licensed material, then the result is a larger work (that consists of different components), for instance a software using libraries, but otherwise if the added materials are not self-contained, not reusable or too tightly coupled with the licensed material (or the licensed material is altered in another manner e.g. parts are removed) then the result is not considered as a larger work, but simply as altered or changed material, for instance a novel where a new chapter is added - or maybe just a missing dot is added. Imagine a licensed material is a photo, you edit that photo and add it with other photos (possibly under other licenses) to a collage. Then you have an altered licensed material (the edited photo) within a larger work (the collage). If you just add a licensed material to a collection where the collected elements exist side by side but with no connection to each other and no coherence or common context, then that collection is not considered as a larger work. For instance if a licensed photo is added to a bare photo collection on a website, then that website is not a larger work if it just serves as the technical medium to provide that collection.