Spammers often use various subdomains and TLDs to bypass general blacklisting of their alleged domain.
Blacklisting an email from @1105.whatacrock.com only works for emails that have the "@1105." but not @1106.whatacrock.com. Each new variant needs to be blacklisted, thereby cluttering the blacklist.
When I right-click on a suspect email and choose to blacklist the domain, MW should offer the option of blacklisting only 1105.whatacrock.com, or substitute the subdomain of 1105 with a wildcard so MW will catch all of them from whatacrock.com.
Also, some spammers will reuse old domains, but use alternate TLDs such substituting the .com with .net, .info, .org and/or adding a country domain.
MW should also offer the option of adding either whatacrock.com or whatacrock.* or *.whatacrock.* to catch all of the variants.
in blacklisting a domain
