This module allows you to get the public suffix of a domain name using 
the Public Suffix List from http://publicsuffix.org

A public suffix is one under which Internet users can directly register names.
Some examples of public suffixes are .com, .co.uk and pvt.k12.wy.us. 
Accurately knowing the public suffix of a domain is useful when handling web 
browser cookies, highlighting the most important part of a domain name in a 
user interface or sorting URLs by web site

WWW: http://pypi.python.org/pypi/publicsuffix/