# Business Interface

Aside from interfaces provided by EIP6239, we also defined various interfaces on the business layer. They are for the following purposes:

* **NameService:** store users' identity
* **Relationship** build relations
  * **Follow:** to build a peer to peer relationship between users
  * **Dao:** to build a grouping relationship involving multiple users
* **Post:** post content
  * **PublicContent:** post public content
  * **PrivacyContent:** post privacy content