Cirrus Insight is a Salesforce app that allows users to view and interact with Salesforce data directly within their email inbox and mobile devices. It provides out of the box integration with Salesforce, including access to objects, fields, and workflows. Users can assign tasks, view analytics, edit layouts, and leverage third party apps all without leaving their email. Cirrus Insight also offers features like email tracking, calendar syncing, and productivity tools to help users manage their day-to-day activities and follow up tasks.