Not all business plans do. Think about it carefully before you invest time and effort. Think about what you want to do. If you like design, don't work for a news site because you'll always be under the thumb of editors. If you're not a hardcore techie, working in a programming based firm will lead to frustration, especially if you don't like Quake and Mountain Dew.
Companies have personalities.
If you're a straight- laced person, a company with openly bisexual folks and the multi pierced and tattooed will throw you off. If your wardrobe is exclusively computer T-shirt, a high profile ad company is going to drive you nuts quickly. If you spent years at IBM and move to a startup, you're going to have to adjust to a different culture. Think that over seriously before you take a job. Well, I'd like to be a senior editor at a news site eventually.