1. Looking for niche domain or institutional/social knowledge produced by experts or insiders for an informed audience that isn't necessarily available in a scientific journal.

Especially with respect to the social sciences and literary analysis, there's a wealth of intelligent commentators that don't surface well on Google without very specific search terms, and the willful subtraction of domains like quora, medium, and tumblr.

They're usually contained on poorly maintained WordPress sites that the author has long-since forgotten about, or as invalid, handcoded html docs hidden in the personal subdomains of university professors and students.

2. Finding online communities that aren't a part of Reddit or a similarly prominent platform