Google Rolls Out AdWords Enhanced Sitelinks Globally
Enhanced Sitelinks look at the other text ads in your account and when it makes sense, they will combine those text ads for your single ad and make it into an AdWords listing with sitelinks. Google said they “incorporate text from ads in your account that are related to your sitelinks,” to make up the new sitelinks.
Google said that their early tests showed that these enhanced sitelinks “could make ads that appear above the organic search results even more useful.” Adding that “they could lead to significantly higher clickthrough rates for an advertiser than regular 2-line and 3-line sitelinks.”
We described in more detail how enhanced Sitelinks work with AdWords over here.