What is a homeowners association?

An HOA (homeowners association) is an association of homeowners formed by the developer when land is subdivided for development. (HOAs are also created by the Master Deed for condominium projects.) The developer records in the land records a Declaration that includes the restrictions, provisions, by-laws, rules and regulations promulgated by the HOA. The Declaration is included as an encumbrance on every unit or lot sold.

HOAs charge a fee that must be paid by homeowners. One of the functions of the HOA is to enforce the private deed restrictions. The HOA also allows the developer to exit all legal and financial responsiblity once the lots are sold off. If blatant wrongs are commited by the developer, State law gives a fixed amount of time to pursue the developer legally. In Massachusetts there is a 6 year statute of limitations.

Now the HOA is handed off or 'dedicated' to the homeowners. HOAs are effectively de-facto levels of government. In many states, there is little oversight provided by the State. The laws that do exist are not accompanied by any enforcement of those laws: HOA lawyers know there is little danger of ignoring the laws. There is no supervision of elections, incombant boards count the ballots, there are no 'opposition party's, HOAs are single party political systems. There is no 'free press', HOA board meeting minutes are strictly controlled by the board. (Owners can publish newsletters.)

Another Answer
Generally, a homeowner's association is an organization set up by the developer of a subdivision, planned community, or condominium, that makes or enforces rules and regulations for the properties within its control. It generally collects monthly assessments for such expenses as repairs, insurance and upkeep of common areas. The association has wide powers, is set forth in the documents that created the development and is recorded in the land records to notify potential buyers. By purchasing a lot or unit in the community the buyer agrees to abide by the rules and regulations promulgated by the HOA. Some are very restrictive and some are more lenient but all have significant legal power.