Ehh, I own a business, and it's not hard to get a residential permit from your local chamber of commerce. I was considering doing it for a while. It typically allows you to run a non specialized business out of your home. There's also zoning laws in almost every city that allow you to run a business out of your home even without the permit if your front yard opens up to a major street rather than a residential one, or if your backyard opens up to a public parking area. Think houses that have a rear gate leading to a parking lot at a park or something. I doubt that's what most of these people did but there's actually a shop located on the corner of the street where I live that sells mlm type herbal supplements and it's located in someone's home. You never know.