Say I have a blog at domain.com/blog/. If I create a page with slug "myname" and parent "about", then I can access it via domain.com/blog/about/myname.
The problem is that if I go and change the page slug to "yourname", the GUID value in the database remains domain.com/blog/about/myname, instead of becoming domain.com/blog/about/yourname.
I'm writing a plugin to walk around the problem described in this topic:
http://wordpress.org/support/topic.php?id=26505
So I wanted to use the GUID value as absolute path to each post/page, but seems that's not possible...