Why not just eliminate the Anonymous Monk user account? IMO, this is the obvious best solution to the problem of spam being posted on PerlMonks.
UPDATE: This little post of mine is currently Number 1 Worst Node of the Week and Number 2 Worst Node of the Month. J'accuse, PerlMonks! If my simple expression of an apparently unpopular (yet seemingly obvious) alternative way to cope with spam on PerlMonks is the worst thing that's happened here so far in August, then I declare discourse on PerlMonks much more f*d up than my post. I down-vote you, PerlMonks!