This is the model that most traditional media is based upon: Magazines, newspapers, network television, etc. Though occasionally there is a small fee (i.e a newspaper subscription) usually a large portion of the cost of the production is paid for by advertisers. Of course they do this hoping that you'll return the favor by purchasing some of their goods or services. Following the old adage that nothing in this world is truly free (everything has hidden costs), all advertising costs are absorbed into the goods that we buy so even if you never partook of the "great" sitcoms that Nike helped make possible through their financial support, you are paying for the costs when you buy a pair of sneakers. Really this model of content support is a form of "content welfare" because regardless of whether or not you buy all no-name food and wear clothes that you stole out of the local Goodwill Box, you can still partake of the subsidized entertainment, so the real cost of advertising starts to concentrate on the guy who wears Nike Shox (could someone please tell me: Do those shoes really make noise? Either they're really goofy shoes, or that is just an oddly misdirected ad campaign, but that seems so silly that it's hard to believe), etc.
This is just a variation on the previous model. Basically it takes into account the fact that content providers advertise in other content providers (usually in different mediums or genres : You don't normally see NBC advertising on CBS, for instance, but you do see newspapers advertising on TV and TV advertising on radio, etc). The point of this is that at the end of the chain we are indirectly paying for every bit of subsidized media that we get. Worse still each transaction increases the "loss" factor: More advertisers are involved, more profit padding is in place, etc. If Jingo is a network show that has to pump the radio and newspapers full of ads, and that draws you to watch it and it is supported by General Motors, indirectly GM paid for each ad down the chain.
Next: Okay, so why doesn't this model work for the net?