Author: Ling Zhang Affiliation:  Independent Researcher Received 1 June 2025; Revised 18 July 2025; Accepted 25 July 2025; Available online 14 August 2025; Version of Record 14 August 2025. Abstract This paper examines Tumblr’s decline from a platform acquired by Yahoo in 2013 for $1.1 billion to its later sale in 2019 for reportedly less than $3 million. It analyzes the strategic, organizational, and cultural factors that contributed to this sharp fall in value, including we