Last March, Google revised their Structured Data Policies. While most changes were relatively straightforward and clear, a few were not. In fact, some policy changes are still not obvious no matter how many times you read over the guidelines. Fortunately, I was able to get some clarification on a few items recently during a meeting [...]
Using Structured Data, you can take advantage of reviews on 3rd party sites. "So if your business has some great reviews on Google+, Yelp, Angie’s List or one of the other many review sites out there and you display the reviews and ratings on your site, you can mark them up."