Another book I read recently, The Long Tail by Chris Anderson of Wired Magazine goes into detail talking about some of the changes in retail brought on my the internet with the main premise (in my words) being that companies like Amazon, Netflix, and Itunes sell fewer copies of a far larger number of items than brick and mortar stores do. Not earth shaking perhaps at first, it makes sense that all of those (and more) can afford to stock a far larger variety of inventory than a retail location. It's a move away from selling the top 10 killer items of the week to selling 10,000 items that will all be useful to someone somewhere.
An example closer to home, I believe SQLServerCentral.com also has a long tail. With perhaps 2000 articles and far more forum posts, it presents a huge surface area to Google (and us) that is wide and one link deep for the most part. It may have changed since the Red Gate acquisition, but prior to that it was amazing to see that of a million page views/month they were scattered almost equally across every piece of content on the site. The nature of the web - and the long tail - make it feasible to publish many of the niche articles present here on SSC. A lot fewer of them would make it into a print magazine or a book because they just would not appeal to a large enough segment.
So if you're thinking of an internet business, look for one that can provide greater variety and depth than a retail store and you might have something. Not sure it works for burgers, dry cleaning, and lawn care, but plenty of other ideas out there!