The Hug of Death is when traffic from a major aggregator — most often 📝Reddit's 📝Front Page, historically Slashdot — overwhelms a destination site's servers, causing it to drop requests, time out, or crash entirely. It is an unintentional 📝Denial-of-Service (DoS) Attack caused by legitimate readers rather than malicious actors. The canonical community explanation lives in a 2014 r/OutOfTheLoop thread.
The Reddit-specific case has its own canonical entry as the 📝Reddit Hug of Death, where mechanics, mitigation strategies, and the modern decline of the phenomenon are documented in detail. The earlier "Slashdot effect" is the term's lineage; the dynamics are identical.