- Coursera is an ed-tech startup providing massive open online courses from top universities to over 2.5 million users, with around 9 million course enrollments. - They needed a search solution for their forums due to the limitations of MySQL full text search in handling natural language queries and relevance at scale. - CloudSearch was selected as it provided fast and relevant searches with low maintenance compared to alternatives like Solr due to its ease of use and integration on AWS. It currently indexes around 1.5 million documents to power searches of their forums.