I don't work at Yelp though I'm pretty sure that the reviews which stay on the website for any length of time are those posted by users who actively use the web

I don't work at Yelp though I'm pretty sure that the reviews which stay on the website for any length of time are those posted by users who actively use the website to search for businesses (i.e., tracked via their cookie) i.e., while there certainly can be paid/manipulated reviews, the barrier to doing so is higher here than elsewhere (e.g., google reviews, tripadvisor, etc.) and there's enough people who are happy to use other less controlled sites, I haven't witnessed any truly widespread fraudulent reviews like I have elsewhere) Generally speaking, I'd say Yelp reviews are, generally speaking, comparatively the most reliable I can't speak to how they sort/present search results - that does seem potentially shady