I think there may be a bug when coping with the path when wordpress is not installed in the root directory. See the following example:

~$ curl -IL http://goo.gl/fb/5lxQ
HTTP/1.1 301 Moved Permanently
Location: http://feeds.feedburner.com/~r/xitong/~3/gxgSlPasM4Q/?

HTTP/1.1 301 Moved Permanently
Location: http://foremire.com/blog/2010/02/udcssa-kungfu/?utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed%3A+xitong+%28Xitong+Liu%29

HTTP/1.1 301 Moved Permanently
Location: http://foremire.com/blog/blog/2010/02/udcssa-kungfu/

HTTP/1.1 301 Moved Permanently
Location: http://foremire.com/blog/2010/02/udcssa-kungfu/

HTTP/1.1 200 OK

Intuitively it produced one redundant 301 redirection:

http://foremire.com/blog/blog/2010/02/udcssa-kungfu/ to
http://foremire.com/blog/2010/02/udcssa-kungfu/

while my wordpress is installed at http://foremire.com/blog/