There's a class of bug that only shows up in knowledge management systems: the invisible overwrite. You open a wiki page in your editor, make a small tweak to clarify a sentence, and save. Three weeks later a query that used to return the right ans...

I want to talk about a problem that sounds simple until it isn't: fetching content from URLs that you don't control. You build a system that ingests web pages. It works great in development, you point it at a handful of reliable URLs and everythin...