If an online business, you need to go into detail how you will attract customers to your website. General statements like "I will use Face Book ads and email marketing" will contribute almost nothing to helping your cause unless you have detailed statistical analysis of tests you have conducted or of another similar business you have been associated with. If you do not have any data upon which you reference your estimates, it could show lack of proper thought to the remainder of your business plan.
The main thing to remember in this section is not to provide new data, but to explain in detail data that has already been provided and to provide the support for that data.
The organizational section of the business plan also needs to include an explanation of your record keeping process, checks and balances, and control management systems. Anyone who reads your business plan should be able to understand the organizational procedures for running your business day_to_day, as well as in an emergency situation.
For an online business, a detailed and in depth business plan is usually not necessary unless you are trying to combine your online business with a traditional business. For most online business startups, the detail involved with planning a traditional business is not required. However, it would still be beneficial to you if most of the topics were still covered, even if only briefly. Having a written plan in front of you will help you to focus on important aspects of the business.