Splunk is a big data company founded in 2004 that provides a platform for collecting, indexing, and analyzing machine-generated data. It has over 5,000 customers in over 80 countries across various industries. Splunk's software can handle large volumes of machine data, scaling to terabytes per day and thousands of users. It collects and indexes machine data from various sources like logs, metrics, and applications without needing prior knowledge of schemas or custom connectors.