Good post by John Battelle on the Looksmart Thought Leadership blog.
"I believe that in the media world, there are several buckets of what one might call "value creation." There is clearly value in traditional approaches to content creation - editors, producers, and writers corralled into media-making factories like the New York Times or NBC (I call this kind of media "Packaged Goods Media"). There's value in a different kind of media, media created by ongoing conversations between communities of media consumers on blogs, social networks, and sites like Digg (I call that kind of media "Conversational Media.")
Finally, there's value in the aggregation and curation of media, whether it's packaged goods or conversational. Curation (or put more traditionally, editing and filtering) is increasingly valuable in the information economy - there are simply too many potential streams of information for anyone to grok, and we need trusted sources to curate it all for us. Google News is a good example of that curation, as are Digg, NewsVine, Wikipedia and any number of other sites - every vertical seems to have similar service - from music (http://www.thesixtyone.com/) to women's interest (http://www.kirtsy.com/).
But here's the rub: There's a critical difference between curation based on algorithm (Google News) and curation based on human insight (Digg or Wikipedia) - and that difference can be summed up in one word: Voice. In short, sites that allow people to be part of the curation process have voice, and sites that are driven by algorithm, don't.
No matter how hard we try, we can't come up with an algorithm that creates a truly human voice."
Worth a read. Also applicable to advertising online I think ... but more on that later.