Avoid hybrid designs on the same level (PS/BU at the same level, hierachial, okay)
If using sites for OU’s, avoid a design which omits a site (same with Business units)
Use OU’s with Delegation of authority instead of child domains when possible (q89)
When mutiple administrators are working in AD, and one moved objects into an OU, just deleted by another admin (but neither DC has replicated yet), the contents of the deleted OU go to the LostandFound folder.
If you delete an OU, the contents of the OU go as well (except per above)
Replication occours at the feature level in 2000; vs value level in 2003 – reducing replication collissions resulting in latest-takes-precident