hehe no ... what you show above is more like what we would consider a standard Redirection....
IR (Internal Redirection) == zzz.com shows the same site as aaa.com but the URL does not change. So unless you were to hardcode the links on the site ppl going to zzz.com see only zzz.com and people who go to aaa.com only see aaa.com neither really knowing the other exists.
IRM (Internal Redirection & Mapping) == zzz.com shows zzz.com but aaa.com shows zzz.com/aaa/ .. the /aaa/ directory works as the root directory for aaa.com -- as such the visitors can view aaa.com without ever knowing zzz.com exists...
If requested -- you can also have the zzz.com's email addy's mapped under aaa.com too ..meaning if you have
Owner@zzz.com and someone emails
owner@aaa.com it will work

(see edit in the threads below)
Sub-Domains == aaa.zzz.com actually uses the zzz.com/aaa/ directory as it's root. So again, the visitor only needs to see aaa.zzz.com w/o being redirected to zzz.com/aaa/
Difficult to explain -- but all are pretty kewl feature
Deb
[This message has been edited by Deb (edited 07-05-99)]