I'm a bit incredulous as I don't really see it as such. I'd venture to say that you still only have ~1% of users creating content with any substance, let alone quality.
As discussed in other threads [0], Letters of Note, for example, provides a context for its instances of curated content that provide a valuable resource for someone interested in the subject matter.
And let's not forget that Google is an example of curation that provides immense value. Google search doesn't provide any new information, but it surfaces existing information in a context that's valuable.
The Internet is increasing full of people linking to content, instead of creating it, and there's a fine line between "curating" links and simply spamming them.
What creates content, arguably, is posting the links in a useful context (and something as simple as knowing your friend likes these might create the context). I think that value is real (and is reflected in services like Twitter), but there are some stark limits because my time/interest in consuming that kind of content is limited. Services that help me navigate the sea of data to effectively find the pearls of interest will have value. But just providing more ocean to search through is of limited direct interest...
Simply posting something that already exists, be it through a Tweet or a link or what-have-you, does not create anything of value.
However, creating said link with a short description or within the context of a greater article does create value. It's not a huge amount of value, but I know that I, personally, am much more likely to examine a link posted by someone if they explain what it is about and that explanation is both interesting and relevant.