In America today, you can connect to your ethnic heritage in dozens of ways, or adopt an identity just for an evening. Our society is not a melting pot but a salad bar, a bazaar in which the purveyors of goods and services spend close to $2 billion a year marketing the foods, clothing, objects, vacations, and events that help people express their (and others') ethnic identities. This is a huge business, whose target groups are the "hyphenated Americans"--In...