Daos are numerous and they are colorful, however there is something in common with all of them, their members agree on something. They could be all possessing the same kind of tokens or they could be writing on the same forum, there is a general consensus between members.
Ricardian Contracts are a new way to achieve DAO consensus.
The Ricardian Contract is semantics hence it can represent many things. A Contract for a DAO could outline it's laws and outline how the DAO works.
An example of this is the Ricardian Fabric DAO, which has a written contract all DAO members must accept which outlines how the builder guild functions and what is required for proposals to pass.
Click on this button to find the DAO terms
By making certain functions in the smart contracts depend on signing this agreement, the DAO is able to restrict functionalities so they are only available for members with rights to access it.
A ricardian contract gives rights to holders, or participants in this case and we can be sure that users with the required rights have accepted the terms , hence we have achieved a kind of consensus between members via semantics.