Go, Read: Gary Tyrrell On Ben Gordon’s Critique Of A Webcomics Profit Model
If you're as fascinated as I am by the increasingly common knowledge that some webcomics creators appear to be making very, very comfortable middle-class livings right now from profits generated by a strip or activity fostered by that strip, you'll probably greatly enjoy Gary Tyrrell digging into one critique of a profit model that's been presented. I think in general we don't have enough samples that last for a long enough period of time to be creating models and we're still in the "holy crap, look at that guy's number" stage.