Application Insights is a Microsoft Azure service that helps application developers understand if their applications are available, performing well, and successful. It provides a 3600 view for developers to be alerted to problems quickly and learn what customers are doing to prioritize work items. The document discusses using Application Insights for Java applications, with the service currently in preview and working towards general availability. It seeks external help with Application Insights extensions and support for technologies like Java, PHP, Node.js, Ruby, and Python.