Google has changed the way sitelinks are shown in SERP

How Sitelinks Are Changingr
We previously discussed the expanded sitelinks, which have been making appearances around the world, although only sparingly in North America. Now Google has made it official, and users "in all supported languages" who are "using a modern browser, such as Chrome, Firefox or IE 7 and above" should see the expanded sitelinks for branded searches.

The expanded sitelinks show a both the title and a snippet of the meta description for sub-pages. Sitelinks will only appear when Google is reasonably certain that a given site is the one you were looking for. If Google is less certain, they'll show you fewer sitelinks.

"For example," reads the official Google statement, "[museum of art nyc] shows more sitelinks than [the met] because we’re more certain you want results from www.metmuseum.org."; At most, Google will show 12 sitelinks.
Additionally, the sitelinks will now contain any well-ranked pages that would have otherwise appeared as a separate entry lower in the Search engine result page will be included among the 12 sitelinks. However, since the expanded sitelinks take up approximately eight times as much space above the fold as previous iterations, that's of little help to anyone competing for position.

While some webmasters have expressed concern, the reality is that Google's algorithm only shows sitelinks for a narrow array of searches. There's a definite user benefit angle, since when Google predicts your target site accurately, the sitelinks work as a quick access point to the core elements of the site.

Google is also experimentally helping users find on-site pages that aren't included in the sitelinks. The following image shows a sitelinks addition that wasn't publicized by Google:

As mentioned previously, the big thing to remember here is that meta descriptions and titles are now even more important, and should be optimized for the small amount of space provided in the new version of sitelinks.
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This is keshav Solanki. I am a Computer Engineer and working as a Online marketing executive from last 2 years. I am a subject matter expert in SEO, SMO and SEM.

So as part of my profession i write articles related to Online Marketing Updates.