Google Search Console has added Rich Card reporting to their interface so that you can see how many impressions and click throughs you're getting on your rich results (aka rich snippets). From Google:

The rich cards report helps you fix errors in any rich card structured data that Google has found on your site. The report also points out areas where you could provide more information to take fuller advantage of Google's rich card platform.

We got a hint that this was coming down the pipeline from Richard Gingras' Google I/O presentation in May.