Schema reviews versus local (Google business listings)
Google displays ratings in their search engine results pages in 2 main ways; the first is most familiar, and it is when Google shows a product’s rating on a given website.
How to get schema.org reviews to display in Google (or elsewhere)
For example, an Amazon product page showing up in Google may also display its rating based on Amazon.com’s Schema.org markup.
Schema.org reviews can be set up on any website by following product or service review implementation. See examples from schema.org and Google.
Get listed in Google places and manage reviews.
The second type of review Google will show is for nearby businesses a searcher may be interested in:
Google manages these reviews on Google places. You can read more about Google local reviews here from Google themselves. Get your business reviewed on Google by setting up a places account and following the information from Google here.