What niche subjects are you interested in for which the knowledge is hard to come by on the internet?<p>Is it due to copyright reasons? Lack of organised and searchable corpus? Hands-on knowledge that doesn't translate well to visual media?
It's barely even "niche," but the <i>inside</i> history of Japanese video games from 1980-1995 is really tough to find information on, aside from the mega-luminaries like the Shigeru Miyamotos of the world.<p>It's unclear how much of this is due to language barrier; maybe there's tons of interviews with those early Japanese game industry types on the Japanese net.<p>John Szczepaniak is one of the few people digging up this history and doing his own interviews with primary sources. He's really done a <i>loooooot,</i> e.g.<p><a href="https://www.amazon.com/Untold-History-Japanese-Game-Developers-ebook/dp/B00Q93N29I" rel="nofollow">https://www.amazon.com/Untold-History-Japanese-Game-Develope...</a>
Not me and I don't know if it's small enough to answer your question, but at my university there was someone doing research in the area of locating and navigating visually impaired people in the outside and inside of buildings.<p>While HCI and indoor navigation is a wide area, visually impaired people have another requirements for UX, navigation hints etc. You need to do things more different.<p>He said that at the time he was doing research there were maybe 50-60 people worldwide who also published papers in the field.<p>So, when he went on conferences 2 or 3 times he met everytime the same people. But he also said that it's far easier to do some fundamental research in this field.
Investing niches.<p>I worked many years as a quant. Strategies based in unpublished findings tend to be very profitable. But once that info becomes widely available it is just a matter of time until getting diminished returns. Thus there is a high incentive to not publicise.