Neal Pollack’s article defending Amazon has many points of interest.  The only one I’ll engage with is that, contrary to the marketing, Amazon is still seeding Kindle Worlds with pro authors under contract–and apparently given advances as well as editorial assistance–to produce “fan fiction” in various authorized Worlds, while anyone else who takes Amazon up on its offer will not get an advance.  Again, I don’t think Kindle Worlds is inherently bad.  I do think that calling it “fan fiction” is misleading; this is not an organic, community-based set of works.  I think it’s important to recognize, when Amazon says that it’s happy with the performance of Kindle Worlds, that it’s very different to write from an advance than not.