Book excerpt: You're either a Purple Cow or you're not. You're either remarkable or invisible. Make your choice. What do Apple, Starbucks, Dyson and Pret a Manger have in common? How do they achieve spectacular growth, leaving behind former tried-and-true brands to gasp their last? The old checklist of P's used by marketers - Pricing, Promotion, Publicity - aren't working anymore. The golden age of advertising is over. It's time to add a new P - the Purple Cow. Purple Cow describes something phenomenal, something counterintuitive and exciting and flat-out unbelievable. In his new bestseller, Seth Godin urges you to put a Purple Cow into everything you build, and everything you do, to create something truly noticeable. It's a manifesto for anyone who wants to help create products and services that are worth marketing in the first place.