The situation students are writing and reading in
In the Truth in Society section of St. Thomas University's Aquinas Program, one of the things students are required to do is to write about local public "Occasions" -- mostly these are on-campus lectures, performances (readings and plays), gallery openings, etc. In order for the Occasion to "count" toward the course requirements a student needs to persuade at least eight other people to attend and to write a public reflection about the occasions; she then also needs to read the other people's reflections and write a response to at least one of them.
These written reflections, then, are intended to be, and are, at least potentially, public documents in a way not much student writing is. At the beginning of the course they are written on sheets of paper and posted on the bulletin board in the classroom (because the section comprises three-flexibly scheduled courses and the room is reserved for this course all day Tuesday and Thursday, students have time to browse through the documents and post their responses). By the beginning of October, however, the venue for the reflections and responses was moved to a World Wide Web based discussion program, and the process of composing reflections and reading and responding to those of others moved to the computer lab or to students' home computers. The program we currently use is called HyperNews; it displays the postings (listed by subject line, author, and date, and identified, crudely, by an icon indicating the posting's relation -- agree, disagree, question, etc.-- to what it's responding to) in an outline format so that students can see at a glance what topics have been begun and who has responded to which, and can read postings simply by clicking on them. In this it is somewhat like the actual cork bulletin board in the classroom, though less tedious to maintain and much easier to read.
All the postings on Occasions from the fall 1997 term except those that were on paper and tacked to the bulletin board in the classroom are available on the course Archive site. It's arranged first logically (the outline form displays responses to postings in indented lists below what they respond to) and then chronologically (within that order, postings are chronological, from top to bottom).
Another characteristic of the situation is that the writing produced is not assessed in any way other than a stated requirement that the postings be "substantial and thoughtful." Students write in a situation where the only response to their text will be instrumental -- that is, it will not be a comment on the merits of their writing or their ideas, and normally it will not be a response from the teacher.
At least one other salient characteristic of the situation students are writing in in this program is that there are many other instances in the Truth in Society experience in which their writing is produced and read in authentically rhetorical situations: they "inkshed," they write email to the staff and to other students regularly, they produce public recommendations for courses of action, which are the basis for class and group decisions; they write reports on which other people base research projects; and they produce, at the end of each term, a published book reporting on a group's investigation of some instance or example of large scale challenges to, or changes, in, beliefs. In each of these cases, I think it's possible to argue that we should see the same kinds of development of shared generic conventions.