EcoblogIT

Dan Brinklin, the co-creator of VisiCalc (the first PC based spreadsheet), maintains a site that I've referred to before and I came across his essay prompted by Chris Anderson's characterisation of the internet's "long tail" (basically the internet allows you to reach a wider audience more easily meaning that previously unsustainably low demand can be sustained commercially).

Dan's is an intersting take on this because rather than just saying that the long tail makes some things sustainable when previously they were not, he says that when designing a product the long tail must be considered if you want it to be a success.