Meanwhile
seems better to start with simpler task like quiting the _s and _k part of
the url, because in a content centered site, the produce ugly urls and are
not much necesary. I will keep you posted.

you can get rid of the _s by enabling cookies. (app preferenceAt: #useCookies put: true)
Pier will also try to remove the _k if possible (for example http://mysite/blog, http://mysite/about etc)