phranque - 5:51 am on Nov 20, 2012 (gmt 0)
Technically there is no rule against using non-ASCII characters in an URL or in any kind of link
while there is a proposal out for "internationalized resource identifiers", non-Latin-alphabet characters in a URL should be percent-encoded.
please see section 1.2.1:
A URI is a sequence of characters from a very limited set: the letters of the basic Latin alphabet, digits, and a few special characters.