Here’s an interesting quote on this subject of how Google searches out your reviews:
Google looks everywhere for review content. The whole of the online world is Google’s oyster and that is true particularly in the review space. Google is not limited to just Google reviews or general review sites for this content. They will look at blogs, magazine or newspaper articles, and industry directories for review content.
The extent to which you can promote your reviews is limited only to your time, effort, and imagination.