The internet may have hastened the demise of "whom", he suggests. The internet has nothing to do with it. It is the fact that grammar is no longer taught. Even at grammar school in the forties there was inadequate teaching of grammar, a view to which I came on experiencing the rigidity of the structure of latin grammar. German, for example, also has a fairly rigid grammatical construction and I suspect that it poses great problems in teaching it if pupils have no concept of cases and how they are used. "Whom" is the correct form for accusative (object), dative and ablative. No-one has the right to retire it. "Who is on who" may be acceptable for colloquial use but should not be used by an educated person in formal company. It is not a question of being understood but being correct. And don't get me started on personal pronouns.