Naming permission level
Using EOS.IO software, accounts can define named permission levels, and each permission level can be derived from higher-level naming permissions. Each named permission level defines a permission. Permission is a multi-signature check threshold composed of keys and/or named permission levels of other accounts. For example, the "friends" permission level of an account can be set so that the account can be controlled equally by friends of the account.
Another example is the Steem zone chain, which has three hard-coded named permission levels: owner, active, and posting. Posting permission can only perform social actions such as voting and posting, while active permission can perform all operations except changing the owner. Owner permissions are reserved and can perform all operations. EOS.IO allows each account owner to define his own permission level and message grouping to promote this management concept.
Permission Mapping
The EOS.IO software allows each account to define the mapping between any other account’s contract, operation or contract and its own named authority level. For example, account holders can map their social media applications to the account owner's "friends" permission group. Through this mapping, any friend in the account can act as the account owner and post information on social media. Even if these friends can post information as account owners, they will still use their keys to sign. This means that you can determine which friends have used the account and in what way.