Several articles have been published about the accuracy and reliability of reviews on Yelp, including The Huffington Post and CBC. Yelp is apparently working on the issue, but I’m not optimistic. Their primary business is advertising; reviews are just content used for SEO, to crowdsource adding businesses, and to engage readers.
My IT in Canada column this week discusses the impact of questionable (I’m being polite) Yelp reviews on a local business. You can read the article here.
Note: I reached out to Yelp for comment, but they did not reply.