Is that true? Some directories like Skaffe, GoGuides  and Joeant have very very deep categories.  And thus it takes a lot of clicks to reach their deep categories. And so does Search Engines spiders. They have to wallow deep down to get to the listings.  So I have been reading up on GoGuide.org where they claim that Google reads their sitemap and if there are additions even in the deep categories, they will index it fast. Do you guys think that is true?

I had thought that Sitemaps is mainly used for naviagtion purposes.