Many of my favorite websites from the old Internet were exactly this, and I think it's sort of a shame that I can no longer find sites like that with Google. For example, I once read a site about this person's journey for the perfect pizza dough. It was obviously a labor of love and he had tried tons of permutations and research into the topic. The site was very web 1.0, presumably doesn't have great SEO, but the guy had better, more in-depth information than anything in the first several pages of the Google search results.
ALL THE TIME when I'm researching topics, I'll think about how there is probably someone out there for whom it's their one true passion, and they have probably put up a little website on some corner of the Internet with more research and depth than 1000 well SEOd blog sites, but it's completely impossible to find.
Edit: I found the pizza website, it was halfway down the second page of google's search results. I only clicked it because it was the only one without a picture http://www.varasanos.com/pizzarecipe.htm