It would help if Yelp allowed new, emerging search engines (potential google competitors) to crawl their site. But their robots.txt only allows Google, Bing and a few others to crawl them (https://yelp.com/robots.txt)
allow all crawlers and I would have at least a little sympathy for Yelp.
allow all crawlers and I would have at least a little sympathy for Yelp.