The beauty of the industry is its incredible variety of sizes and shapes. There is no singular definition. What you'll find below is PAII's attempt to delineate some differences and define some similarities. The hosts are primarily interested in meeting new people and making some additional monies while continuing their present employment or retirement. Frequently located in residential areas, zoning or other government restrictions may prevent the use of signs, public advertising, etc.
Breakfast is the only meal served.
In some instances, it may be an unhosted apartment where breakfast is self-serve. It is located in a legally zoned area and meets all the tax, fire, building and health requirements for this size and use of property. This establishment advertises publicly and can legally post a sign. Reservations are made directly with the property. Generally small, owner-operated businesses providing the primary financial support of the owner.