SEO Question:
My site already ranks number 1 in Google. How do I get Google to post a mini site map in the search results?
SEO Answer:
I believe that Google primarily displays multi link listings when they feel a query has a strong chance of being navigational in nature. I think they can determine that something is navigational in nature based on linkage data and click streams. If the domain is well aligned with the term that could be another signal to consider.
If you have 10,000 legit links for a term that nobody else has more than a few dozen external citations for then odds are pretty good that your site is the official brand source for that term. I think overall relevancy as primarily determined by link reputation is the driving factor for weather or not they post mini site map links near your domain.
This site ranks for many terms, but for most of them I don't get the multi link map love. For the exceptionally navigational type terms (like seobook or seo book) I get multi links.
The mini site maps are query specific. For Aaron Wall I do not get the mini site map. Most people usually refer to the site by it's domain name instead of my name.
Google may also include subdomains in their mini sitemaps. In some cases they will list those subdomains as part of the mini site map and also list them in the regular search results as additional results.
Michael Nguyen put together a post comparing the mini site maps to Alexa traffic patterns. I think that the mini site maps may roughly resemble traffic patterns, but I think the mini links may also be associated with internal link structure.
For instance, I have a sitewide link to my sales letter page which I use the word testimonials as the anchor text. Google lists a link to the sales letter page using the word testimonials.
When I got sued the page referencing the lawsuit got tons and tons of links from many sources, which not only built up a ton of linkage data, but also sent tons of traffic to that specific page. That page was never listed on the Google mini site map, which would indicate that if they place heavy emphasis on external traffic or external linkage data either they try to smooth the data out over a significant period of time and / or they have a heavy emphasis on internal linkage.
My old site used to also list the monthly archives on the right side of each page, and the February 2004 category used to be one of the mini site map links in Google.
You should present the pages you want people to visit the most to search bots the most often as well. If you can get a few extra links to some of your most important internal pages and use smart channeling of internal linkage data then you should be able to help control which pages Google picks as being the most appropriate matches for your mini site map.
Sometimes exceptionally popular sites will get mini site map navigational links for broad queries. SEO Chat had them for the term SEO, but after they ticked off some of their lead moderators they stopped being as active and stopped getting referenced as much. The navigational links may ebb and flow like that on broad generic queries. For your official brand term it may make sense to try to get them, but for broad generic untargeted terms in competitive markets the amount of effort necessary to try to get them will likely exceed the opportunity cost for most webmasters.