I have been watching and occasionally assisting in the development of the Wikipedia entries on Hard science fiction and Space opera. Neither of these entries are terrible, nor — having watched them progress for a while — do I anticipate that either is going to get much better.
Since there are not commonly shared theories of literary genre underpinning the evolution of these articles, they tend to devolve into something reminiscent of the end game of a game of life when the little groups of pixel enter a repeating pattern; cycles of argument about whether a work or writer is or is not hard sf, as if this was as easy to decide as something like nationality; creeping expansion of the list of Space opera games, suggesting that regardless of what the main text of the article says, this was all just a prologue to an explosion of computer games. Which is to say, because the nature of literary genres is for the most part poorly understood, the real action on such subjects is the exploration of tangents.
While in some ways, this is like the many sf convention panels on such subjects, at the end of the panel, people leave and go off to do something else, whereas this progresses with no end in sight.
What we end up with is a kind of mushy, common sense-based set of definitions that are probably endlessly reused in high school and college class papers, but which don't really get one very far. One reason for this is that genre definitions are partly a function of competing strong points of view by writers and critics; such disagreements are a key element of genre definitions, and for the most part aren't represented in the Wikipedia definitions of genre.UPDATE: The Wikipedia entry on the New Weird is left as an exercise for the reader.