A friend sent me a link to Paul Graham's recounting of the old story of the poor student who enjoyed the smell of fish cooking in the restaurant next door, and who was sued by the restaurant-owner, who claimed the student was stealing the smell of his food. Graham uses the story to suggest that intellectual property rights are subject to an evolving definition and implies (though he doesn't say it in so many words) that they are evanescent.
But this is a poor analogy.
The owner of the shop is not selling smells; he is selling food and the smells escape freely from it, the same as from the food other people sell. He does not usually charge for smells or even, under normal circumstances, treat them as a commodity. There is no comparison to intellectual property (except perhaps to people who can't tell the difference between creative work and the smell of cooked fish).
A better analogy would be if I bought your products and offered them as free gifts for new customers at my bank. I have the right to do that since I've paid for them. But I can't pretend that there is no condition to be met in order to receive a gift, and I would be insincere if I said my entire goal was to distribute your products. But that is exactly what the advertising industry does by using Internet search results as a lure to expose us to targeted ads and subject us to data-mining. It is still possible to avoid the ads — you can use tools like Adblock Plus and you can conduct all your web-searches through a browser that doesn't link searches to a known login (I like iCab for this purpose, while logged into accounts on more mainstream browsers).
Graham's post is primarily about "labels and studios", the high end of the entertainment business, which are a primary force behind the perpetual extension of copyright in the United States, the fictitious electronic security that is an increasing drag on our economy, and recent legal threats to end the freedom of the Internet. "Labels and studios" are easy to vilify. But the idea of intellectual property doesn't belong to them, and not everyone who owns intellectual property is guilty of their excesses.
To pretend otherwise is disingenuous and provides tacit support to the huge, powerful technology/advertising companies that now treat the entire content of the Internet as a resource with which to make money.
I make all my work freely available on the internet, but it remains copyright and its use is not free in the sense "unencumbered", even though it is free in the sense "freely accessible" and may be copied at will for individual reading and study. There's a clear statement of this principle on the site. My feeling is that if you use my stuff to make money, you owe me a cut.