Following on from my earlier comments, I believe that there is an RFC saying
that domain names should be 3 characters or more, but one I have just come
across, São Tomé (.st).

They state in their policies and rules:
"What characters and how many characters can a ST domain have?
You can register domain names with as few as one (except for the reserved
address space - characters A - Z) and as many as 23 characters are
permitted. Names may not begin or end with a dash. Upper case and lower case
are treated as lower case only. Spaces and any other characters in a name
will not be accepted. Accented names are not accepted."
>From http://www.nic.st/rules.html.


Cheers
David