For sending, receiving and storing mail under your own domain (you@xyz.com), our shared server accounts fit the needs of most organizations perfectly.

Shared server accounts give you private space on a server that is shared with others who have the same type of accounts.  You have no access to anybody else's data, and in fact can't tell that any other accounts exist - it's as if you have a fully dedicated private server.  Our servers are extremely fast and lightly loaded, so performance is always excellent.

You can set up as many email boxes as you like - the only real limit is disk space.  You can control how much space is allocated to each user, so you won't have to worry about one user using up more than their share of resources.  

You'll have a control panel that you, as domain administrator, can log onto, which will let you set up, change or delete mailboxes at any time.  You can set up forwarding to other addresses, autoreponder messages, change passwords.  You can give your users access to private control panels for their own accounts, which will let them make their own password changes, set up their own out-of-office autoresponders, etc., reducing your administrative workload significantly.

You can use POP3, IMAP or webmail (each domain gets its own private webmail portal) to access your mail. Users who want to acccess their mail from multiple locations should use IMAP, which is designed to leave the mail on the server so it can be accessed from any computer.  Those who want to download their mail to one computer and automatically delete it from the server should use the POP3 protocol.  The choice is up to you.