Interestingly, the typo "meghathread" has become a coded signal. Because Reddit's automated filters are trained on the correct spelling ("megathread"), users now intentionally misspell the term. A post asking for a "Meghathread for books" is less likely to be auto-flagged than the correct spelling.
The Megathread was (and in preserved forms, still is) a gigantic, categorized wiki page or stickied post containing links to:
It was maintained by volunteer moderators and trusted community members, with constant vetting of links for malware, dead domains, or honeypots.
If you stumble upon an archived PDF of the old r/Piracy megathread, be cautious. The landscape of piracy changes weekly.
Red Flags in a modern "meghathread":
Safe practices if you find a current one: