Originally Posted by yanni

They're called IDN domains [ Internationalized Domain Names ] and they've been around since 2000. The 'xn--' part is called punycode anf its the ASCII representation of the domain.

They get type-ins, especially Russian IDNs, since Opera is in wide use in Russia and it auto appends '.com' when you enter a keyword in the address bar and hit 'Enter'.

Opera also keeps the Unicode part of the domain visible in the address bar instead of the punycode. [ i.e. Opera will show ノーパン .com instead of xn--ldkg6h8a.com ]
Firefox and IE display the punycode 'to protect users from phishing attempts'