Concurrency in Go is a powerful feature that enables developers to handle multiple tasks simultaneously, which can greatly enhance the efficiency of applications. This lesson focuses on implementing concurrency in a practical way, specifically through the counting of multiple files concurrently, thereby enriching an existing application. Key topics include understanding the foundational concepts of concurrency, such as thread synchronization and race conditions, as well as utilizing Go’s unique channels for communication between concurrent functions. Additionally, the lesson revisits previously discussed algorithms for counting bytes, words, and lines from an `IO.reader`, setting the stage for performance comparisons of different algorithms related to data streaming in future modules. By mastering these concepts, developers can optimize their code and harness the full potential of Go’s concurrency capabilities.