Splunk is a software platform that allows users to search, monitor, and analyze machine-generated big data via a web-style interface. It collects and indexes data from various sources like servers, networks, sensors, and applications. Splunk is used by over 9,000 customers across various industries for security intelligence, IT operations, and business analytics. It offers role-based access controls, multi-tenancy, and secure data transmission. Splunk components include universal forwarders for data collection, indexers for data storage, and search heads for data presentation.