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.
You may not have thought much about your competition or outsourcing some of your work, but things like that will impact your ability to make a profit. And you will find this especially so in the beginning phases of your business. Even you are just opening a lemonade stand in the front yard, you will still need to know what Susie is selling her lemonade for on the next street over!
Management and Operations: Because management problems are the leading cause of business failures, it is important to discuss management qualifications and structure. Resumes of the Principals should be included in supporting data. If your business will have few employees and rely heavily on outside professionals, list these key people and their qualifications. If you are seeking financing, include personal financial statements for all of the principals in the supporting data section.
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.