EDIT: Enshittification, also known as platform decay, is a process in which two-sided online products and services decline in quality over time. Initially, vendors create high-quality offerings to attract users, then they degrade those offerings to better serve business customers, and finally degrade their services to both users and business customers to maximize short-term profits for shareholders.
For me it started in 2006 when OLGA went offline. OLGA was a community of people who transcribed how they played songs on guitar, and the music industry decided that they held the rights to that and sent a takedown request.