Yes surprisingly people do make money writing fake reviews for the website yelp and other business listing websites.
Although yelp isn't the one that pays you for the reviews.The companies hire what is called middle men who then outsource the review writing to freelancers.
To find the work you need to search on craigslist and other classified websites. You might also look on freelancer and see if any paid to write review for yelp and other website jobs exist.
The jobs do exist especially if you look on craigslist but they might also exist on freelancer or other freelance websites.