We dont set user's password as identified globally . We write identified globally to decide user's scope.

Details:

In Oracle we can create user in three ways:
1. local user
2. external user
3. Global user

Different commands to create these users:
We create local user as:
create user user_name identified by password_string........;

We create external user as:
create user user_name identified externally as .......;

We create global user as:
create user user_name identified globally as .......;

Difference in the scope of these users:

local user always requires a password to log in to oracle no matter what.

External user will not require any login password as local user does.
Such a user will be authenticated by operating System. Means: If you can log in to operating system you can use oracle too.

GLobal user will also not require any login password as local user does.
Such a user will be authenticated by a directory service .. like OID (Oracle Internet Directory). This service is used when we have enormous number of users who use oracle and we want to maintan them from one place centrally.

I think this much information is enough for interview perspective.
If you want to understand it in details.
Visit oracle documentation available online.
You can visit this : http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_8003.htm#SQLRF01503


Thanks
Param
oraclescoracle dot blogspot dot com