If you need to get going quickly to ride the wave of a fad before it fizzles, then fast, bare_bones planning may be all you've got time to execute. This works best when you've already got the infrastructure in place, perhaps from previous projects or an established business, and you can simply shift energy and resources to the new idea.
As I conclude, I would like to advice all people, who want to start any kind of business or who already have business without a business plan, to think about creating one as way to building a successful business. One of the causes of failure in business is lack of proper planning. Create a business plan if you want to succeed in your online home business!