Karon Thackston explains that “when spiders find some hearty “spider food” (a.k.a. a site map with some meat to it), they sit down to stay a while. That’s a good thing!” She also explains how you can “beef up” your site map so the spider-bots will notice.
“If you really want to fill the spiders’ bellies, you’ll want to take your site map page to the max with a descriptive site map (as I like to call them).”
“Descriptive site maps work well in attracting and satisfying spiders because they include naturally occurring keywords.”