Google just made some modification on how many links from your sites to be displayed on search results “if” you site qualifies to have one. According to their blog,

We’ve also been tweaking things here and there so that Sitelinks will appear for many more websites, and with more descriptive names. These improvements should help get you to the specific page you’re looking for even more quickly.

If you have a good content, you can have one as far as google decide you have the site that considered on this sitelinks features.
Question is, how can you site become one of those having this thing when you search for some keyword or key phrase?
1. Good Quality Content - if you can give juicy information to google, well you can be a candidate.
2. Better Site Structure - take a look at sites having this google quick links. Check how they structure their site for better user and bots experience.
3. Popularity of your page - if a certain page or directory of your entire sites get more traffic than others, the probability of including it on sitelinks is very high.

There are other ways to please google and have that sitelinks features, all you need to do is work on your sites. For those what to know sitelinks, when you search for a keyword you will see some quick links below the site listing result. Example i search for yahoo, below are the site links

You see the quicklinks below yahoo, but I wonder why google.com itself don’t have this?

Does this means none of google other pages don’t have the quality ? Just kidding!No!, they can do whatever they want on their own site and search engine.