Already DOTCOM-SEO have chat with MATT regards GOOGLE site links
now, Yahoo also started that same works :) mmm… good competition.
"Yahoo Quick Links are little links found beneath some of the search results at Yahoo Search. As an example, a search on " barry schwartz " at Yahoo Search brings up a Wikipedia entry for the other Barry Schwartz with Quick Links; it looks like this:
In my example above, I showed you how Wikipedia results have Quick Links. In fact, Wikipedia is part of a "pilot program" where Yahoo is testing out the user experience before deciding if they should expand the program to roll out more quick links. At this point, Yahoo did not confirm if they will doing so or not.
more details : http://www.ysearchblog.com/archives/000255.html