Most part of the world uses non-ASCII characters. But some idioms use things like é, ö, á, ã, õ etc, which can be "converted" to ascii.
Suppose the title of the post is:
Configuração é fácil!
How to represent that in a URL?
www.myblog.com/post/1200/Configura__o-_-f_cil
A much better representantion is
www.myblog.com/post/1200/Configuracao-e-facil
Wikipedia do that as in http://en.wikipedia.org/wiki/Deja_vu
Will this improve page rank in search engines?
How to do that in your favorite language?