A quick search for a local restaurant shows yelp as the top hit. Google shows a info box to the side with their own reviews. I don't see a problem with this,

A quick search for a local restaurant shows yelp as the top hit. Google shows a info box to the side with their own reviews. I don't see a problem with this, and I can't imagine it being illegal. Companies are allowed to cross-promote between their services. Changing this would go far beyond tech companies.