Can a user be a member of multiple Organization Units (OU) in Active Directory ?

Question

Can a user be a member of multiple Organization Units (OU) in Active Directory ? Also, is there a standard format mentioned by Microsoft on how an OU should be created and what its attributes are ?

I found this in Wikipedia

"However, Organizational Units are just an abstraction for the administrator, and do not function as true containers; the underlying domain operates as if objects were all created in a simple flat-file structure, without any OUs. It is not possible for example to create two user accounts with an identical username in two separate OUs, such as "fred.staff-ou.domain" and "fred.student-ou.domain"."

Answer 1

Can a user be a member of multiple Organization Units (OU) in Active Directory ?

No.

Answer 2

No.

As you mention yourself:

However, Organizational Units are just an abstraction for the administrator, and do not function as true containers; the underlying domain operates as if objects were all created in a simple flat-file structure, without any OUs.

You can copy a file to another location in your file structure, however you can only have a given user only once in the directory forest. Therefore you can't add it to multiple OUs.

And in my opinion there is no use in adding a user to multiple OUs, since they don't serve as real AD groups. If you really want some hierarchy then you should build a hierarchy of OUs.