If you're striving for a top ranking for that very competitive keyword, you may discover that the first search result on Google lists more than one page for a particular site (often commanding the first AND second spots on search result listings). I've personally always wondered why this occurs and how I could replicate the success seen by other top ranked website.

What are Google Site links?
Google Site links are a collection of links that appears below the result of a website. These additional links link to main pages of the website. They are randomly and automatically chosen by Google's algorithm.

Site links only appear for general search terms. You'll get Site links if you search for "HP" but you won't get Site links if you search for a term like "HP printer supplies". Site links show up most often for searches on brand names.

Which links does Google use for the Site links?
Google seems to use the first level links on a website for the Site links. That means that all links that are not present on the homepage of your site won't be used as Site links.

The links should be descriptive text links or image links with a descriptive image, alt attribute. JavaScript or Flash links are not considered for Site links. Google uses 2 to 8 links for the Site links of a website. Unfortunately, it's unclear how Google assigns the number of links to each website.

The text that is used for the Site links can be the text that are used for the link (anchor text) on the homepage or the title of the linked page. It seems that Google prefers links that appear at the top of a web page.

How can you get Site links for your website?
Unfortunately, there is nothing certain about Google's Site links. The following factors seem to influence whether Google displays Site links or not:

1. Your website must have a stable #1 ranking for the searched keyword. Other websites don't seem to get Site links.

2. Your website must be at least 2 years old. It seems that younger websites don't get Site links.

3. The number of searches and the number of clicks that your website gets for a certain keyword seem to be considered. Keywords that aren't searched often enough don't get Site links. It also seems that your website has to get many clicks for the searched keyword.

4. The number of links that point to your website with the searched keyword as the anchor text seem to influence the creation of Site links. Site links only seem to appear for the main keywords of a website, not for all keywords for which a website is listed.