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.
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.
Right now, growth may sound like an unattainable goal as businesses are grappling just to survive, but hey, "flat is the new up." If a business can keep its doors open and lights on, then it's doing better than many others. But lights and open doors don't make sales, so making changes that attract business is in a sense, striving for growth. It won't be this tough forever, but for now, putting some growth strategies into action may be what keeps your business alive, if not thriving.
Understand gaps and weaknesses within the plan. Any casual viewer of the BBC programme, Dragons Den will be aware of how easy it is for weaknesses or gaps to be identified. Depending upon the purpose of the plan, this may, or may not, prove to be critical. It is often easier to recognise such weaknesses and gaps, and be prepared to deal with them, either by noting them in the plan itself, or having appropriate answers available should the need arise.