Book excerpt: del.icio.us offers millions of Web users an online social network in which to collect, organize, and share their favorite web resources. Using an underlayer of tools offered by del.icio.us, you now have the potential to tap into this social network in order to expand your own website to a whole new array of possibilities. This book will help you make the most of these possibilities and encourages you to use your own innovative ideas to create something useful, unique, and even fun.