As of May 1991, the goal is under 100,000 bytes. Decisions regarding content may be made based upon this, though in general it shouldn't be an issue. Don't assume that people will pick up the context from your writing. Tell them explicitly. Let us know your point of view.
Anonymity is acceptable, though most people want to take credit for their work.
Include full contact information including electronic mail addresses. It is not the intent for this to be a mechanism to refuse articles the editor does not like, but simply to keep the contents intelligible. If we have a backlog of articles, we may get fussier about things. Historically, this has not been a serious problem. If all that hasn't scared you away, the next step is to create a text file which contains the text of your article.