This was inspired by this thread of lazy's in the SW Fanfic Resource. All writers worry about how much they ought to describe stuff, but on cross-fandom boards I've found that there's an additional issue of picking a target audience. Authors write for an audience who is "in the know" differently than they do for people who are entirely new to a particular universe. Worse, re-explaining everything that led up to a scene may turn off your fandom regulars, while not explaining at all may lose your new readers. So how do you solve the dilemma of how much background information to include? Alternately, what (if anything) is the bare minimum you need in order to follow a fic set in an unfamiliar fandom? If you know a fandom, what details do you just not want to hear explained again as long as you live?