Well in general actual spam *should* get caught by the Junk E-mail Filter.
Especially when you have it set to High you might occasionally need to
unblock a person or entire domain to have it filter correctly. Individual
blocking can be usefull when you just get tired of some newsletters and you
fail to unsubscribe. Domain blocking is not that common for actual spam
since the domain name changes with each mail. Therefor I think this option
is just a little further away then the others. But feel free to suggest it
to the Product Group; http://office.microsoft.com/assistance/suggestions.aspx
