UserSessionCookieDomain
Returns the value of the UserSessionCookieDomain
configuration setting,
or the domain name of the blog currently in context.
Any "www" subdomain will be ignored (ie,
"www.sixapart.com" becomes ".sixapart.com").
The UserSessionCookieDomain
may also use MT tags.
If it does,
they will be evaluated for the blog in context.