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:
http://www.ietf.org/rfc/rfc3986 [ietf.org]

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.