As Mathew Ingram introduces: "The principle behind copyright has been taking a beating from "remix culture," driven in large part by YouTube and other video sites."
There are a number of creative activities you can put in that "remix culture" and though curation is not a challenge to current copyright law as it doesn't change the nature of the original content, it is probably part of its broader definition.
What's interesting is that the first challenge to copyright was piracy. But the remix culture has nothing to do with the motivation to get content for free: it is about creating the new from the existing, just like DJ's remix and sample songs to create new pieces.
Interesting to watch how this wave will shape the future of publishing.