I've been wondering this myself and the new RC presents the most worries for me. (Are we all supposed to stop reading the Economist, now?)
I actually did this experiment where I cut up an article and removed every alternating paragraph, but this really seems too random. I think what I got from that was that the Economist has wa-a-ay lots of detail and you can skip reading half and still feel informed about the topic.
Krause, how have you been approaching it?