However, mint has no ads, doesn't charge for the iPhone app I use all the time, has never spammed my account in any way... the only thing mint probably does make money from is commission from banks for referring new customers, but if mint can provide unbiased information about why switching from one bank account type to another can give me some sort of benefit (and in my limited experience, it has), it's a mutually beneficial relationship.
I am aware there are costs to providing a service, but when you provide them at no cost to your customers, that is not piracy.