The financial statements section should show the way things are now if you have an existing business, as well as a forward look at your checking account, or projected income statement. The only way a start_up company can provide an income statement and balance sheet is by projecting these figures based upon well defined assumptions. Both start_ups and existing businesses should include a statement of owner's equity.
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.
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.
Personnel: The success of any company depends on their ability to recruit, train and retain quality employees. The amount of emphasis in your plan for this section will depend on the number and type of employees required.