How to find old threads

Found a link to a 2ch thread that is not active anymore and has been moved to the archives? You could always buy archive access (about $30/year) but there's many people archiving popular threads on their own.

If Google (just search for your thread's title) or archive.org fail, there's always these two nifty sites:

2ch-Library - collects a variety of really popular threads, categorized neatly by boards/topics:
http://2ch-library.com/

makimo.to - has a HUGE automatically maintained archive of 2ch threads, dating back years and years. You may not find the most recent archived threads there, though.
http://makimo.to/2ch/index.html