The idea of renting out a room in a house or an apartment is nothing new. Neighbors have been upset about it since the beginning, too. Here’s what they decided in 1916:

Justice Kelly, in this Ditmas Park case, holds that a boarding house is a business when it is the sole means of support of the person who conducts it, but that a family with a means of support which takes in relatives or friends as “paying guests” is still a private family.

The letter at the end describes the neighborhood quite nicely.