The document discusses best practices for streaming applications. It covers common streaming use cases like ingestion, transformations, and counting. It also discusses advanced streaming use cases that involve machine learning. The document provides an overview of streaming architectures and compares different streaming engines like Spark Streaming, Flink, Storm, and Kafka Streams. It discusses when to use different storage systems and message brokers like Kafka for ingestion pipelines. The goal is to understand common streaming use cases and their architectures.