Lists are a way to organize and work with data. Learning to effectively use lists is one of the most important tasks in building good apps with App Inventor.
Lists serve an important purpose in general programming as well. Consider how a news app has lists of sections. Think about how a social network, such as Google+, has lists of a user’s friends. App Inventor has an easy-to-learn but powerful method for implementing lists into mobile apps. Any collection of data can be represented as a list or as multiple lists working together.