When Importing mass of users, it's not possible to review user mapping by hand.

Then it should provide a way to automap users based on strategies. The first strategy proposed is:

• If LDAP id exists => use found user
• Otherwise, if username match => use the found user (even if email differs)
• Otherwise create user (even if email is found)

This is intend to be used in environment where LDAP provides a strong consistency for ldapids and usernames (like ActiveDirectory)