Not sure there's a definitive answer, Google says only this: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=47334
It's an automated process; when "Googlebot thinks" they are appropiate and useful to your visitors for navigation reasons, they will appear. Has nothing to do with the quality or size of a site. I maintian client's sites with less than 50 pages and they recieved sitelinks.
I searched the Google and found this http://www.vmoptions.com/articles/article-3.html Sitelinks are only displayed on the top listing for any given search. Normally, you will see these when searching for a specific company name. Google has indicated that Sitelinks are only displayed if their algorithm can determine which of your pages would qualify for Sitelinks. And it is important to note that Google displays these not for webmasters, but for those using Google’s Search. If there is one thing the Sitelinked Websites have in common is an easy to navigate Website. The main categories (those useful for Sitelinks) stand out from the rest of the links. Generally speaking, your main category pages should appear as Sitelinks. Those main categories may include your business profile, company history, contact page, etc. If you have a product line of four or five products/services, they would also be great for Sitelinks. Since Sitelinks are dependent on a Website’s structure, this is something we have control of. To help Google find the pages you would like Sitelinked, the best practice is to link to those pages twice on every page of your Website. Many Websites have a left navigation structure that points to the main internal pages, which is fine. But we really want to highlight our main internal pages even more. Therefore, it is important to also link to these pages on the footer. Please look at the example link structure below. Product | Product 2 | Product 3 | Company History | Contact Us Notice how each page has a separator. This is very common among the many Sitelinks I have seen. If needed, use two lines for your main category links. There is a limit on the number of sub-pages that will be listed for a Sitelink, and from what I have seen eight is the limit. The wording of sub-pages listed in a Sitelink can include anchor text, image alt text, and the url name (ie. widgets.htm would list as Widgets in a Sitelink). In creating Sitelink friendly pages, keep these considerations in mind. The goal here is to create consistency. So if you have images that link to your main categories, use alt text that matches the anchor text of your footer links. Some Sitelink search queries return a link to a map. One thing that is common among these listings is a clear and concise contact page that lists the company name and address, as if it was written for an envelope. Also, the font size is larger then the text on the rest of the page and is not cluttered among advertisements or other text. How Google qualifies pages for Sitelinks and maps is something we may never fully understand. However, we can come to some relatively strong conclusions by examining who already has Sitelinks! Regards Tehmina
Make your site the best it can be, add lots of useful content and claim that number one spot. Then make sure you stay there for a few months and the sitelinks should follow!
Nice information Tehmina. A local organization where I live has 6 pages indexed by Google, and those 5 sub pages are it's sitelinks. One other common thought for sitelinks is that the site needs to have been ranked #1 in Google for awhile. I am not sure if this is true or not, however I have seen a site with sitelinks that was not ranked first. So, perhaps they were and got bumped off, so it was recent and the links hadn't been removed yet.
Its not guaranteed, but making the main links more visible to search engines help. For example if you put the main categories at the very top, that would work. But I am not sure if a website got to earn some authority to get site links or not.
Yes Friend, Google will provide site links but You have to maintain Quality content + quality links in Your web pages. you can see your site links in Google webmaster account when google'll find quality in your pages. Thanks Eric
We don't need to do anything special for sitelinks. Google will count sitelinks for a website when they consider them appropriate. So we just need to keep on doing the good work.
I think that site links are purely based on the quality of your site and the value of the information to your reader. If you have a spam site, you are unlikely to get any. The best way to improve your chances is to create good quality content
i have observed for my site that site links are give to the page for which i am running adwords. The landing page is treated more useful by google and shwn in sitelinks, however which is not what i think..
There seems to be alot of these vague, hard to decipher posts... but there is some good information here - thanks!