https://en.wikipedia.org/wiki/Sitemaps
Sitemaps may be an intelligent auto generated way of suggesting to search engines what should be covered as a priority.
There have been reports of the members profile section being higher ranked, likely due to its rapidly updating nature, instead of the topic display.
http://www.elkarte.net/community/index.php?topic=4270.msg30678#msg30678
@Vekseid seems to have done some of the harder graft on it already and has offered it. Currently it doesn't support pretty url's.
https://github.com/Vekseid/ElkMapGen
http://www.elkarte.net/community/index.php?topic=3256.0