We’ve talked about the importance of using ad extensions a number of times in the past. The two main bulletpoints for their use is that ad extensions are part of the ad rank formula Google uses to determine where your ads appear on the SERP page and ad extensions allow you to grab a larger piece of SERP real estate thus higher visibility and more clicks. Indeed in many cases sitelinks are shown to generate considerably higher CTR than the ad!
Google recently began rolling out a new ad extension this one called Structured Snippets. This extension shows under your ad copy and above any sitelinks. Like Callout extensions they are not clickable and are meant to provide additional information to the searcher. These are a bit more restrictive then either sitelinks and callout extensions as you must use a rather limited set of “headers” including Amenities, Brands, Styles and Courses. So for example if you are selling a particular type of running shoe you can choose the Style header and enter a list of different running shoe styles available. Or you can select Brands and enter a list of different running shoe brands you carry.
It does appear at this point that Google is going to display the snippets in the order they are listed. So your first snippet appears first, snippet number two appears second, etc. Something to think about when giving this a test drive.