Echo Chamber

Legal scholar Cass Sunstein established the modern meaning in Republic.com (Princeton University Press, 2001), arguing that online self-curation would create ideologically sealed information environments corrosive to democratic discourse. Sunstein built explicitly on Nicholas Negroponte's "Daily Me" concept from Being Digital (1995) — Negroponte had envisioned personalised news positively; Sunstein identified its democratic cost. The figurative use of "echo chamber" in political contexts dates to at least the 1930s, but Sunstein's 2001 work gave it its current sense.