The question is asked for the difference between the pirsuma nissa of chanuka which requires us to light menorah at our doors or windows, and pirsuma nissa of purim where we lein megilla but from inside a shul/house out of view of the street.
The answer could be as mentioned earlier, that the main ness of purim was that when mordechai instructed esther not to reveal her religion or background, she listened and told no one!! To commemorate this, we keep the secret also and read the megilla not out by the street but from within the privacy and seclusion of our shul or home.
Shhhhhhhhhh!!!!!