Last week's Science Friday had a discussion on exactly this topic
http://www.npr.org/2012/08/17/159003121/arbiter-of-interestingness-navigates-the-net
"Maria Popova, editor of brainpickings.org (and the über tweeter behind @brainpicker), describes herself as an "interestingness hunter-gatherer obsessed with combinatorial creativity." Popova discusses her work, and explains why she thinks the blogosphere needs a "curators' code."
http://www.curatorscode.org/
When I heard this episode, I wondered if we should adopt it here. On a voluntary basis. Usually I try to include a "via this website"; but I don't more often than I do.