So, although a detailed business plan may not be required for an online business, I am going to include it here so you can at least look at and consider each section and determine yourself if it applies to your business.
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.
Competitive Analysis: Business by nature is competitive, and few businesses are completely new. If there are no competitors, be careful; there may be no market for your products. Expand your concept of competition. If you plan to open the first roller skating rink in town, your competition will include movie theaters, malls, bowling alleys, etc.
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.