Looking good in Google is not just about vanity. By having Google ratings stars, you are telling search engine users that they can interact or vote on your content or products. This shows visitor engagement on your website and will likely lead to an increase in your click-through-rate (CTR) within the search results (i.e. people are more likely to click on your site link when a star rating is applied versus a search engine snippet that has no stars). And because the stars that appear in the search engine pages take up an extra line of space, it draws extra attention to your listing, especially if your competitors don’t have stars. Search engine users also attach more trust to companies with search engine snippets ratings, even if they only achieve a one-star rating.
Google, Bing, Yahoo and Yandex all support star rating in search results, also known as rich snippets. A collaboration between these search engines has lead to the creation of the schema.org project, whereby a shared markup vocabulary has been developed to help webmasters to easily add structured data to their web pages that all search engines should be able to understand.
Most webmasters are familiar with the HTML tags on their web pages. The HTML tags tell the web browser how to display the information within the tags, but they don’t give any information about what the text within tags mean. This is where Schema.org markup comes in – the extra tags, along with microdata format adds information to HTML content.
For instance, if you hosted a web site that sold Stanley Kubrick DVDs, you might have the following HTML tag on your web page: