Ask YC: crowdfiltering business case

NewsYC, Digg, Reddit are top of the top crowdfiltering services, and I think that they get more visits because they are designed to bring change/news more often than a regular blog.

Also, the final result it's better news for the visitor.

Do you have more information about this pattern?

I'm building an engine to run sites like this, with the same features that reddit or digg has, and would like to put it in production soon, but need research about how benefits a community to put a site like this online.