After the successful implementation of schema.org for critic reviews last year, Google has focused on supporting more types of reviews, like restaurant reviews, cafes, or any other type of a Google local business.
Recently Google announced the availability of critic reviews for local businesses. Critic reviews are available across mobile, tablet and desktop, allowing publishers to increase the visibility of their reviews and expose their reviews to new audiences, whenever a local Knowledge Graph card is surfaced.
Schema.org was basically developed in collaboration between the top search engines. That attempts to devise a method of categorizing and identifying information about different websites.
English reviews for businesses in the US are already supported and we’ll very soon support many other languages and countries.-said Mr. Jaeho Kang- Software Engineer at Google.
Mr. Kang also states that, Publishers with critic reviews for local entities can get up and running by selecting snippets of reviews from their sites and annotating them and the associated business with schema.org markup.
This process, allows publishers to communicate to Google which snip they prefer, what URL is associated with the review and other metadata about the local business that allows Google to ensure that they’re showing the right review for the right entity.
Google is also able to understand a variety of markup formats, including the JSON-LD data format, which makes it easier than ever to incorporate structured data about reviews into webpages.
For more information, you can visit webmaster forums.