[svat]

Secretaries were part of academia (something that came with his professor job). What is unique to Knuth is not the existence of a secretary, but his (attempted) refusal to receive emails except about bugs (but those he gets thousands of, as everyone in the world is encouraged to report bugs to him about every page he has ever written).

Anyway, Knuth's secretary (shared with several other faculty members) retired from Stanford several years ago (he dedicated one of his books to her), and although he hasn't updated the page, in fact he does all his own email now. (There is someone who comes in once a week to send his replies in the post — if you email Knuth about a bug you may get a reply a few months later from this person, asking for your postal address to mail you the reply: this will be a printout of your email, with Knuth's reply in pencil… and an enclosed cheque if your report/suggestion was accepted.)