Viability
The pure freeware model of software development has been criticized as "unsustainable" because it requires a single entity to be responsible for updating and enhancing the product, which is then given away for free. Most successful freeware products have been ad-supported or "freemium" in which the free product serves to promote a commercial offering. Other freeware projects are simply released as one off programs with no promise or expectation of further development. These may include source code, in the case of open source software, so that users can make any required or desired changes themselves.
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