The popular press would have you believe that it's easy, everyone is doing it and all you need is a modem and an idea. The facts are not encouraging. In this gold rush of the 90's, like the California version in the 1880's, more money is made selling picks and shovels than will be made with dust and nuggets. You shouldn't take my word for it. Just visit a hundred or so sites and note that nearly everyone lacks a clue about selling.
Most web sites are just linked lists.
The bane of education. The lost Dutchman's map of phrenic science. The first users of the Web were college students whose lives were ruled by bluebooks and lists of facts so it is not unexpected that THEY would devote their spare time to swapping electronic lists of T-shirt collections, CD collections, shareware for sharing, etc. Why grown-up businessmen would follow suit defies understanding. My real admaker friends cringe at overhead projectors.