This is a very big conceptual jump from thinking in terms of business plans. This estimate will take into consideration the past and the present and project these into the future with suitable allowances being made for uncertainties and errors of judgement. As carefully as these business plans might be worked out, they can only be as accurate as the uncertainties inherent in the future period will allow. The errors are unlikely to to be covered by even the most cautious of projections or the most far reaching contingency plans. It highlighted the problem by listing a number of initial assumptions that any planner in the e-business environment would have to make before setting out the details of a business plan.
Nobody knows all the answers.
The environment of the Internet and the World Wide Web is beyond your or anyone else's ability to be able to understand it completely. Everybody is mostly too busy for you to be able to get their attention. Most people haven't the time to listen to what you have to say. Whatever you know, there are many more important things that you ought to know but don't. Nobody is going to cooperate with you unless they see there is something worthwhile in it for them.