Google Sub-Sitelinks

Google is now showing what they call "sub-sitelinks" for some searchers in the search results. Sitelinks are the links you find under a search result that show links to popular pages within the site. This often comes up for navigational searches, for example a search on [search engine roundtable] and tons of other queries.

Google is now showing some searchers sub-sitelinks, so sitelinks for sitelinks. Here is an example of it in action provided by Google Operating System blog. As you can see by the animated GIF I made, the sitelinks show with arrows down, when clicked, they show secondary sitelinks.

Here is a larger image provided by @6cSocial:

This is not the first mention of Sub-Sitelinks. In fact, we had this show in Google Webmaster Tools back in October 2009 and then Google made mention of it in May 2012by saying:

"Sub-sitelinks" in expanded sitelinks. [launch codename "thanksgiving"] This improvement digs deeper into megasitelinks by showing sub-sitelinks instead of the normal snippet.