Slightly off topic, but one of my favorite episodes from that podcast actually aired right after Derek Siver's interview: http://foolishadventure.com/audio/write-compelling-copy-with...

It was definitely worth a listen and included a ton of practical tips on copywriting. The one that stuck with me the most was to "steal copy from your potential customers", for example, look up customers' Amazon reviews on your competitors to see how they're describing products.