Separate www from @ (SOA domain) in domain tagging

In many instances, the www subdomain points to an IP different than the actual domain (also named SOA or @) in DNS.

Since right now it is impossible to correctly tag www subdomains as domaintagging interface defaults to the actual @ domain it is impossible to tag some domains correctly.

For instance, all sites hosted by Google Sites are hosted only under www subdomain since Google does not allow to point the SOA domain in its cname alias configuration.

Another example: www.diode.es is a different host and site than diode.es: www is the actual website while diode.es is apparently the interface to corporate firewall.