The e_marketing plan is built exactly on the same principles as the classical plan. There is no different approach, but there might be some formal differences given by the uniqueness of the internet environment. Many of these differences come from the necessity to ensure a high rate of responsiveness from the customers, since the e_world is moving faster and requires faster reaction from its companies, compared to the traditional offline marketplace.
Risk _ in our marketing plan we shouldn't only concern about making money or positive points, we also should address the risk we are taking. for example it is common for a marketing plan to capture things like, "require additional staff to handle sales call", "additional investment from the management budget will increase chances of increasing 10% sales target" and many more. Imagine if you can factor your risk earlier and think through it, wouldn't it be better for you?