Examples of that data are user-generated content on social media sites, blogs, comment fields, and wikis etc.
It may also include other public data sources like press releases, news, blogs, legal filings, reviews and job postings.
Some social media monitoring and analytics companies use calls to data providers each time an end-user develops a query.
Additional monitoring companies use crawlers and spidering technology to find keyword references, known as semantic analysis or natural language processing.
Basic implementation involves curating data from social media on a large scale and analyzing the results to make sense out of it.