Survival analysis of 423,265 pages with Wayback Machine histories shows pages on politically controversial topics have substantially shorter lifetimes than those on uncontroversial topics; topic change — not just page deletion — must be treated as 'death' for probe-list purposes, since a page that switches topic no longer contains the sensitive material that made it censorship-relevant.
From 2017-weinberg-topics — Topics of Controversy: An Empirical Analysis of Web Censorship Lists
· §6.1
· 2017
· Privacy Enhancing Technologies
Implications
Circumvention tool evaluation suites should use continuously-refreshed probe lists and discard URLs whose content has changed topic; stale lists overestimate how much sensitive content a tool actually unblocks.
Prioritize testing circumvention access across topic categories (news, politics, human rights) rather than fixed URL sets, since individual pages turn over faster than the categories censors target.