Homeowner Associations are self-governing committees that plan for and enforce rules for a community. Residents of condos and other communities commonly come together to make rules and guidelines that mutually benefit all residents of the building.
There are usually mandatory membership fees for a HOA as well as fines for noncompliance. HOAs can pay for shared community maintenance (eg. parking lots, landscaping) but may have high costs that make uneconomical to invest in.