Why you should not markup reviews from Yelp, Google Maps and others.

Search Engine Land reported last month that it’s okay to post reviews from other sites (like Yelp, Google Maps, etc.) on your website. However you should not mark them up with schema.org structured data as this is against Googles guidelines. The reason is that the markup is reserved for reviews “directly produced by your site” and not copied from other sites.

So please keep that in mind when adding structured data to your reviews.