Contracts are agreements between 2 or more parties which are based around and enforced by the law, if you were to break this contract you would most likely be breaking the law and end up in court. Contracts are almost always written down as proof of it ever existing.
They’re many different kinds of contracts:
Employment Contract: The contract you would sign when getting a job some where. This contract would have you agree to all the regulations set in place by the employer so if you break them you could be fired.
NDA (None Disclosure Agreement): This is a contract you would sign when working on a project that isn’t public, it would either limit or completely stop you from being to speak about it openly. You also sign these when testing early build games.
Development Contract: This is a contract between a developer and a publisher, it will cover who gets what out of the profits, production on sequels, what would happen if either party is dissatisfied.
Distribution Contracts: These would be between the Publisher and Distributor, it would cover the release date, special editions, collectibles and exclusive content.
Advertising Contracts: This would be between the developer and the publisher, they would use the contract to agree on things such as the style. how much they will spend on the advertising, what kind of content the advertising will have and who will be doing it.
An example of a contract being broken and being taken to court would be the Fallout MMO case between Interplay and Bethesda , where they were fighting over who had rights to its IP. They were also claiming that releasing the Fallout Trilogy pack would have caused confusion since it included Fallout 1, 2 and Tactics instead of Fallout 1, 2 and 3. In the end Bethesda payed $2 million for Interplay to end their claims against it.
I believe contracts are a very good thing as they assure that all the parties will do as they promised and if they don’t they will be able to do something about it.