PlanetScale provides a serverless database service that is compatible with MySQL, focusing on scalability, performance, and reliability for developers managing large data sets. Its features include horizontal sharding, non-blocking schema changes, built-in connection pooling, and Data Branches, which create isolated copies of databases in the cloud. This approach simplifies complex database management tasks, allowing developers to work without downtime or the need for staging environments. The goal is to enhance the developer experience by enabling seamless scaling of applications.