Taco Bell: "Tweet us your photos of you with your free biscuit tacos, Instagram us and also Snapchat us.""We're always in beta and trying things out," said Ms. Friebe. She said that approach resonates with the way young people, who were born into technology, experience things. "[Our consumers] are used to living in this world where people are constantly trying something, seeing if it works and making changes."Taco Bell is also transporting consumers back to their childhood with inventions like Cap'n Crunch Delights, a doughnut hole inspired by the classic cereal, as well as ads like "Unboxi...