Interesting article.  People are lazy, make it easy for them or they’re not going to do it.  And let’s face it, a little recycling is better than none, right?  Single stream may degrade the materials and amount, but isn’t that offset by the fact that more people will do it?

These days, some cities are making recycling as mindless as possible by implementing "single stream" recycling, in which paper, metal, plastic, and glass are all mixed together in one bin. Should this be our standard nationwide? Proponents argue that it makes people more likely to recycle; others counter that the quality suffers. Miller is all for simplicity, but says single stream "degrades the material and reduces the amount that can be made into new products."

http://www.motherjones.com/environment/2009/05/recycling-fuhgeddaboudit