One of the positive things to come from our prominence has been the rise of similar subject-specific resources - many clustered around Wikia, but not all. For any supporter of free culture it is a deeply heartening thing to see a genuine focus on creating free content for a variety of purposes.
There are obvious benefits to finding ways to work closely with these projects. For one thing, it promotes free culture, and that is our goal. For another, these projects often fill in gaps in our coverage. It's a simple fact of life that our most-read articles are often ones on fictional subjects. And we have major controversies in this area as people seek to restrain our coverage due to notability. If we can interface ourselves with fan wikis for various shows we can also better police the boundary between what we want to cover and what we don't want to cover without leaving our readers short-changed.
In fact, this is often a major argument raised in notability discussions - if people want plot summaries they should go to X Wiki.
Years ago, I created http://en.wikipedia.org/wiki/Template:FreeContentMeta to help with this - it was a base template that could be used to create sister-project like boxes for other wikis. This let us, on fictional characters, have a link much like we have for Wikiquote or Wikisource that basically said "If you want detailed in-universe information, here's where to go." This struck me as common sense - it helped with the problem of getting readers to expect us to provide what we actually provide, it helped editors have a better sense of where to put different types of information, and it helped free content by creating prominent and crawlable links to free content resources (since Wikia is on the interwiki map, and thus links are not nofollow).
Unfortunately, the templates are pretty near to being deprecated with no real replacement in mind. This strikes me as very, very unfortunate - the attitude, which seems to be that we ought never promote anything, ever, and that we have no obligation to help other free content resources, seems to me both a case of pulling up the ladder and of situating ourselves as a walled garden. We want people to go to other resources instead of us, but we are unwilling, it seems, even to tightly integrate with those resources to make that leap easy for readers. The idea that we have an obligation to help free culture is roundly and dismissively rejected, and the very idea of providing prominent links to free content sites is decried as an NPOV violation (though nobody, to date, has explained what viewpoint it unfairly advances...)
What can or should we do in this area? How can we best use the existence of a much larger galaxy of free content resources to improve ourselves and improve them? What role do we play in the larger free culture community? Are we a walled garden that is only to be imitated? Or are we the leaders who can and should use our prominence and our muscle to help create free sources of knowledge for anything that people want to know?
For me, this is a no-brainer. So how do we do it?
Best, Phil