Audience and Purpose

When developing a writing, the readers you are trying to reach become your audience. Much of what you say and how you say it will determine your audience group. It also depends on the type or groups whether they are general people or experts in the related fields. "Even the way you organize your writing and the amount of detail you include (The terms you define, the amount of context you provide, the level of your explanations) depends in part on what your audience needs to know". The term audience tends to drive two different directions of people. One towards actual people, the other towards the text itself and the audience implied there. The purpose is to make the audience see what you see, hear, and feel. Revelant detail, and language is the best way to recreate what happened.

Reference:
R. Diyanni and P.C. Hoy II, (Scribners handbook for writers. Allgn 2001)
Douglas B. Park " The meaning of Audience" College English, 44, 1982)
Richard Nordquist,(About.com guide)