We argue that healthy OSS projects must be financially supported by methods such as charitable means, grants, or commercialization, in order for the development of the project to be sustainable. We discuss a few commercialization models that have become popular with OSS, which try to strike a balance between supporting openness and supporting future development. It is worth noting that these strategies are not necessarily mutually exclusive.  Dual licensing: A popular commercialization option for OSS has been to offer the software under both a strong copyleft license (like GPL or AGPL) and a more permissive commercial license. The code itself is typically the same for both license types. The difference lies in how the code can be used, modified, and redistributed depending on the license under which it is acquired. Projects using this strategy are often available under a strong copyleft license (GPL, AGPL, etc.) with no financial cost.