Dead Internet Theory: Public web archives capture what an anonymous visitor can read, so anything behind a login quietly sits outside the record. The Yahoo Groups shutdown shows how a twenty-year archive of communities escaped public capture, and how authorized members saved what they could.
Dead Internet Theory: Streaming audio and video is not a file a crawler can copy, so page-level archives save the player and miss the stream. The British Library's One & Other case shows what was lost, what survived, and what a complete capture has to include.
Dead Internet Theory: How robots.txt, a file written for search-engine crawlers, has decided which pages get archived and which stored captures can be seen, and what a missing capture actually does and does not prove.
Dead Internet Theory: Many pages are built separately for each visitor, so one URL can stand for dozens of different versions. A web archive captures only the version its anonymous crawler happened to get, and reading that capture later takes context the archive does not store.
Dead Internet Theory: Why a saved page can open blank, broken, or behind an error wall even though it was captured, and how to tell a replay failure from a real archive gap.