Improving on AdWords sitelinks which was introduced in 2009, Google is now introducing what they call, "Enhanced Ad sitelinks".
Sitelinks are known to increase click through rate of an advertisement by 30% on an average, when compared to those without them. After continuously experimenting in an attempt to make them even better, Google now will be incorporating text ads in the AdWords sitelinks. In other words, if ads in your account are related to your sitelinks, then they will now be shown in AdWords listing too. Here's an example to show you how things will change:
Suppose you've have already created a sitelink for a pizza restaurant, which looks like this:
Now suppose the account also includes following text ads:
Once current enhancement takes place, your ad could now look like this:
Google have further said that “To be eligible, your ad with sitelinks must show above Google search results and your account must contain active ads closely related to the sitelinks in your campaign”.