The URL Mapper
module is used to Map and Redirect non-existent URLs to existing URLs.
This could be useful in situations where you have moved your site from another location to jamroom. If the previous sites CMS was something like wordpress, it may have used urls with extensions like site.com/?p=156
Search engines may still be sending users to those urls. The URL Mapper module can be used to redirect them to the content they are looking for.