An article in yesterday's New York Times revisited the still-unsettled arena of interlinking, excerpting and what constitutes "fair use" in online publishing. Specifically, the reporters found that as online advertising revenue dries up, many publishers have implemented a strategy of keeping their content fully exclusive in hopes of monopolizing what money that content may bring in. But what many publishers overlook is that it's not the mere act of excerpting that boosts or erodes the original publisher's work, but more importantly the context and quantity of the excerpting.
Every self-respecting online publisher knows the two-fold strength of an inbound link. From a traffic perspective, inbound links are the short-term influx of readers to a particular article (for smaller publishers, a link from a larger and more highly-visited site can make a world of difference in traffic numbers). But these links also help a site establish credibility to both an audience and to the technical underbelly of the internet; an article has not only made its point, but an inbound link also means that article (and, in a larger sense, the site hosting it) is now important to a second site as well.
In the case of excerpting, the general consensus holds that a good repurposing will put forward what is good about an article without removing a visitor's incentive to read it. This is not unlike common rules of atrribution in the news industry, such as using the phrases "As first reported by [rival news outlet]" or "As [source] told [rival news outlet]." While the laws on the subject are still in rough draft form, the informal marketplace of the internet has generally worked against blatant theft with impact on any meaningful scale (witness the recent savaging of the Huffington Post's Chicago arm).
As long as there is an internet, there will be scraper sites that steal volumes upon volumes of content, but publishers need to realize that (a) those sites never make any real money and (b) full-scale copyright infringement suits are still there to help publishers if those scrapers ever do.