You need to provide evidence or a sense of where you're coming from, yes. But sometimes just tying in two disparate links can do that.

http://scrapbook.akkartik.name/post/4424779/are-crowds-wise-...

I make it clear what data I'm summarizing, but the summary also seems more timeless to me than the data. I can imagine it being derived from other books about the wisdom of crowds. Like this blog post:

http://gojko.net/2008/08/05/bulding-smart-teams