Hi - Thanks for the replies. I am still confused, but I think I can ask questions that will clarify things. First, FYI I am an experienced Unix user (started with v6 at UC Berkeley in 1976) so I think part of my problem is I am trying to map what your use model is to how it matches a typical Unix system.
RLParker: I read both those pages before I made this post. Re-reading the pages after a long discussion with my wife - who is an experienced hosting user - and reading AndrewF's post I think clarifies things. The wiki page on account layout was confusing because it talks about sub-accounts and yet the page notes that sub-accounts do not exist anymore. I couldn't tell what was left and it was structured when they were removed from that description.
Here's my interpretation of things.
I create a Dream Host (DH) account. This account has an owner which is an FTP user. By account here I mean a business relationship tied to a credit card. Now, it seems that you create a Unix Account (UA) in /etc/passwd or some other authentication mechanism for that user with the shell set to FTP - or more likely a script that launches FTP. A domain is linked to this account - probably by doing a DNS bind to your main server.
I can create shell users which presumably also creates a UA but with the shell set to whatever is select on the add-user panel. Shell users can do FTP and email.
I can create mail users who can only receive/send email through the domain.
I can create other "accounts" for web, stats, backup, etc with privileges as noted in the wiki.
Along with your system you probably have a database (mysql no doubt) that maps DH accounts to UA (e.g., so you can delete all /etc/passwd entries when someone deletes the DH account). This DB probably has other mappings, but if every user gets a UA maybe not. For example, I could imagine that you modified SMTP incoming server to lookup mail user names in a separate DB rather than /etc/passwd so that people in different domains could use the same user-name. I am guessing that when a mail sender sends email to email@example.com, the SMTP server could do a database lookup using the key and respond to the VRFY command and determine where the spool file is to store the mail message. But, since you create a UA for every user, this is probably not true.
NOW, my questions.
Is there a limit on the number of "users" that a DH account can create? I.e., can I have 5 FTP users, 10 shell users, and 50 mail users?
It appears that you use a email address and password to select the control panel for a domain (e.g., my domain is rowehome.net and my login is larry "dot" rowe "at" gmail "dot" com). Does this mean I need a separate email account for every domain I host at DH? That's our current situation - my wife registered greyscalewines.com with a different email address. That is fine with me since I can use her "login" to access the greyscalewines.com control panel.
Finally, how could the wiki be clarified to answer these questions. First I would take the "Users" page and add a section "Introduction" before FTP users where you describe the architecture of a DH account - i.e., the business relationship - which has a controlling FTP user. Then I would say that an account can have other users for the domain - you have the note that user names must be globally unique, but I didn't really get that when I first read the page. I was too confused by FTP users, Web users, Shell users, etc. I would be this note in the Intro. Then, talk about how many different kinds of users a domain can have - if there are restrictions. Then, put the details about the types of users into subsections like you have already done.
Second, I would redo the account layout page to remove the sub-account description. Those are pretty images that describe things, but frankly I did not read them that carefully since I wasn't sure what still existed.
FINALLY, thanks for the quick responses to my questions. I'm impressed! :)!