---
id: "prereq-network-effects"
type: "prereq"
source_timestamps: ["§ Transaction fees"]
tags: ["strategy", "competitive-advantage"]
related: ["concept-everyone-loses-together", "contrarian-moats-become-liabilities"]
reason: "Necessary to appreciate the contrarian insight that platform moats become vulnerabilities against AI."
sources: ["attention"]
sourceVaultSlug: "hbr-seg-attention"
originDay: 4
articleStem: "hbr-foci-69-ai-threatening-platforms"
sourceUrl: "https://hbr.org/2026/04/how-ai-is-threatening-platforms-revenue-streams"
sourceTitle: "How AI Is Threatening Platforms’ Revenue Streams"
---
# Network Effects and Moats

**Prerequisite knowledge.** Familiarity with how digital platforms use **network effects** to create 'winner-take-all' monopolies and defensive **moats** is assumed by the authors when they explain how AI agents reverse this dynamic into 'everyone-loses-together.'

**Why it matters:** Necessary to appreciate the contrarian insight — [[contrarian-moats-become-liabilities]] — that the very moats that once conferred advantage become the surface agents arbitrage against, producing [[concept-everyone-loses-together]].

**Enrichment pointer:** See Evans & Hagiu on network effects and competitive dynamics in multi-sided platforms.


## Related across articles
- [[concept-habit-moat]]
- [[concept-everyone-loses-together]]