Citation Network of Section 230 of the Communications Decency Act: A Validated Corpus of Published Federal Circuit Appellate Holdings, 1997–2025

This deposit provides the data and code for a computational legal study of Section 230 of the Communications Decency Act (47 U.S.C. § 230). It includes a validated corpus of 69 published federal circuit opinions that substantively applied § 230 immunity doctrine between 1997 and 2025, the citation network constructed from those opinions (69 nodes, 357 directed edges), all derived network metrics, and the complete analysis pipeline.

Version 2 correction: Version 1 contained 70 corpus cases and 360 edges. Version 2 removes CourtListener cluster 3048087, a superseded pre-amendment panel opinion in Perfect 10, Inc. v. CCBill LLC (filed March 28, 2007), which was superseded by the amended opinion at cluster 3048873 (filed May 30, 2007), reported at 488 F.3d 1102 (9th Cir. 2007). All analysis data files have been regenerated against the corrected 69-case, 357-edge corpus.

The corpus was constructed by retrieving 211 candidate opinions from CourtListener and subjecting each to systematic human review against a documented operative inclusion criterion and a ten-pattern exclusion taxonomy. The false positive rate in automated retrieval was 67.3% ((211 - 69) / 211), a methodological finding with implications for corpus construction in empirical legal studies. Corpus recall was 1.0 (95% Wilson CI: 0.960-1.000) based on a stratified sample of 19 cases across five temporal strata.

Key findings: citation authority concentrates in Zeran v. America Online, Inc., 129 F.3d 327 (4th Cir. 1997), which holds PageRank 0.202, accounting for 20.2% of total network authority; the Leiden algorithm identifies 6 communities (mean NMI stability = 0.672 across 100 seeds); mean pairwise Jensen-Shannon divergence between circuits is 0.654 bits, increasing from 0.519 bits in 2003 to 0.654 bits in 2025 with no convergence event; mutual information between community membership and immunity outcome is 0.155 bits (NMI = 0.124, permutation test p = 0.023, n = 10,000 permutations, seed 42); Fair Housing Council v. Roommates.com, LLC, 521 F.3d 1157 (9th Cir. 2008), holds the highest betweenness centrality in the corpus (BC = 0.019) while ranking fifth by PageRank.

All data and code are provided to support full reproduction of all analyses. See README_ZENODO.md for the complete file inventory and replication_guide.md for step-by-step reproduction instructions.