Because SMTP was an open protocol. No MUA company profited from its end user seeing spam. No end-user-targeted MTAs (i.e., the MTAs of most end users' ISPs) also found spam as a cost center. (I'm being pedantic here in…
Because SMTP was an open protocol. No MUA company profited from its end user seeing spam. No end-user-targeted MTAs (i.e., the MTAs of most end users' ISPs) also found spam as a cost center. (I'm being pedantic here in…