This game is played in "real time", on a timeline that corresponds with the real world. Please do not, however, backdate LiveJournal posts; this could cause people to miss entries. If you need to backdate something, note it in the text of your entry.
Please use descriptive subject lines. Mark non-IC posts with an OOC tag. Otherwise, title posts, "Letter to character: general short subject", i.e., "Email to Joe: Weird camping trip" or "Letter to Sally: Summer school sucks". You may write correspondence to NPCs; just indicate that in your subject, like, "Postcard to Janet (NPC): Paris". Characters writing to themselves, i.e. journals or diaries, are also appropriate; give them a title of, "Journal: subject" or something similar.
Please make use of the LJ-CUT tag for any post of more than a paragraph! This works as follows:
<LJ-CUT TEXT="Text of link to click on.">
... remainder of text
You are writing about your own character's experiences. Character interaction outside of the letters is possible, but discouraged, since it makes coordination complex. Consequently, the characters you create should be physically separated from the other characters, preferably in such a way that they would not logically frequently see the other characters.
Don't use other people's characters and settings without permission, except to reference something that they've written in a letter to your character. Of course, you also shouldn't assume that other characters will necessarily tell the truth in their letters!
You own your own work, and you may edit or delete postings that you are dissatisfied with. However, by participating in this game, you agree, as a courtesy to the other players, to not mass-delete or edit your posts in a disruptive manner. In other words, you can do with your writing what you please, as long as you're not wrecking the game for the other players.
Write whatever you want, but keep in mind that you should be writing in the spirit of Lovecraft -- things from the dark that man was not meant to know. This is Cthulhoid horror, but X-Files-ish elements are potentially appropriate -- the key is the sense of the unknown and the unfathomable. You are writing what may be a slow descent into insanity -- but it's not inappropriate for characters to write more casually about their lives, as well.
We're all adults here. If you're going to write something particularly gory or disturbing (beyond the normal level of such things one might expect out of a Lovecraftian story), though, please post a warning at the top of your post.
This post will be amended as needed over time.