Media pluralism is the presence of diverse sources, viewpoints, and access paths in the information environment. In cyber security, it matters because information systems can be attacked or manipulated without breaking into them: ranking, recommendation, and automated curation can quietly narrow what people see, making one source or narrative dominate. When users encounter only repeated viewpoints, they are easier to mislead, profile, or steer.
In real attacks, pluralism is weakened by coordinated amplification, bot-driven engagement, synthetic media, and feed manipulation that push one message across many channels. Defenses focus on diversity and transparency: multiple trusted sources, provenance checks, platform logging, non-personalized feed options, and monitoring for inauthentic influence campaigns. Strong media pluralism does not stop all misinformation, but it makes censorship, manipulation, and single-point control harder to sustain.