Unfortunately, taxation and finances aren't my forte, so your guess is as good as mine on that.
But in some cases, a not-for-profit organisation could set itself up as a front for fraud. Basically you inflate your required expenditure to maintain your business (administrative costs, maintenance, resources, transportation costs, etc) and free-load of the discrepancy donations give you, instead of allocating them aside for future use. That's one way a website owner too, could conduct fraud I think, but like I said, I'm hardly an expert on the subject.