DaveN at ThreadWatch posted his love/hate for Google Sitemaps, but what I find to be the most interesting part is the discussion taking place in his post at his blog. Vanessa Fox, Google Engineering, from the Inside Google Sitemaps blog posted a comment at Dave's blog explaining why a the Sitemaps query stats may say you come up for a popular term even though you don't mention that term or phrase on your pages of your site.
I do not want to miss anything from her comment so let me quote them.
(1) Stats are based on three week averages; "They are averaged over a three week period, so any big fluctuations during that period may make the stats seem off."
(2) "They are top overall queries. For instance, say your site isn?t about Britney Spears, but you?ve mentioned her a few times and so your site ranks for her (although likely doesn?t rank well). Your site is actually about purple apples. So, if a million people search for Britney and 10 people search for purple apples, then Britney is going to show as a top query. And you might look at that and say, my site isn?t even about her. How can that query be higher for my site than what my site is actually about? But in sheer number of searches, Britney is a top query for the site."
And to clarify number two, we have this comment;
My early morning, under-caffeinated guess is that you linked to this threadwatch story (http://www.threadwatch.org/node/7076) in your ?industry news? section and at some point, that may have been on the same page as links pointing to this post: http://www.davidnaylor.co.uk/archives/2006/03/21/naked-truth-about-shoemony/ and possibly some anchor text pointing to your site includes the word ?nude? (the cached page info seems to indicate so). And when searching for christine dolce naked became a popular thing to do, your site may have been an early one to have all the keywords.
This explains a bit more about how Google Sitemaps query stats data works.