One-way text

I just came across the most elegantly insightful aphorism (in the middle of a discussion of synecdoche† in fan-fiction, e.g. referring to people by profession or eye colour rather than name): fanfic is writing whose primary function is to be written rather than to be read.
† Edit: I'm not sure that is in fact the right term, but it was the one being used...

It is regarded as a means above all of self-expression rather than of communication, created to satisfy the need of the author, who "writes to get their own personal enjoyment out of it, with little thought given to what reading it feels like" -- a chorus of squee and flailing is nice to receive, obviously, but basically it is an outlet for the writer's feelings rather than an attempt to create prose that will draw an audience. (Who might not, for example, want to plough through several paragraphs of authorial analysis about the background of a minor character as an interruption to a dialogue passage, or conversely might be cringing every time they read badly-formatted dialogue or exchanges between "the red-haired marksman" and "the tall brunet"[sic] ...)