The "Friendly" slogan he started out with was because:

*He left notes for the police after trapping bad guys in a web,

*He was always quick with the quips

*he helped little old ladies across the street and such

*He went on talk shows every now and then

In short, he was the most relatable costumed hero to New Yorkers. Not the most respected -- that will always be Captain America -- but he became a classic "Noo Yawk character" to the public.