Key ideas to study for the exam on April 4, 2006

1. Samuelson CACM articles on the MGM v. Grokster Supreme Court case. (paper 1, paper 2)
   • The Sony "safe-harbor provision" and its role in the MGM v. Grokster case.
   • The "active-inducement theory" of patent law and its role in the MGM v. Grokster case.
   • Judge Posner's "cost-benefit test" from the Aimster case and its potential implications for the IT industry.
2. Incentives Build Robustness in BitTorrent, by Cohen (Cohen) (paper)
   • Basics of how BitTorrent trackers work (Section 2)
   • Basics of how BitTorrent peers work (Section 2 - see also Figure 1 in SPM below)
   • Iterated prisoners' dilemma (IPD), tit-for-tat, and their roles in modeling BitTorrent choking and unchoking (Section 3).
3. Faithfulness in Internet Algorithms, by Shneidman, Parkes, and Massoulié (SPM) (paper)
   • Review of the notion of "faithfulness" covered in the first part of the course and explained informally in Section 1 of SPM
   • Types of rational users, including Speed-critical users and Free-riding users (Section 4)
   • Difference between beneficial manipulation and harmful manipulation (Subsection 5.1)
   • Manipulations available to BitTorrent clients (Subsections 5.2 and 5.3)
4. Incentives in BitTorrent Induce Free Riding, by Jun and Ahamad (JA) (paper)
   • JA's proposed incentive mechanism and how it differs from Cohen's original proposal (Subsections 3.1 and 3.2)
   • Properties of winning IPD strategies identified by Axelrod (Subsection 3.3)
   • Interpretation of experimental results (Section 4)
5. The Social Cost of Cheap Pseudonyms, by Eric Friedman and Paul Resnick (paper)
   • What the authors mean by "cheap pseudonyms" and why iterated prisoners' dilemma (IPD) accurately represents the online interactions that they are interested in (Sections 1 and 2)
   • Localized punishment strategy (LPS) and its properties (Sections 2 and 3)
   • Public Grim-Trigger Strategy (PGTS), Public Forgiving-Trigger Strategy (PFTS), and their properties (Sections 2 and 3)
   • Pay Your Dues (PYD), Propositions 2 and 3, and Corollaries 2 and 3.
6. A Game-Theoretic Framework for Analyzing Trust-Inference Protocols, by R. Morselli, J. Katz, and B. Bhattacharjee (paper, slides)
   • Adversarial framework and notion of "pseudonym" given in Section 2
   • Definition of "robustness" given in Section 2
   • Robustness and optimality of Grim Trigger (Lemma 1 in Section 3)
   • Robustness of Pay Your Dues (Theorems 1 and 2 in Section 3)