Explain "users" to us. Who have you provided email accounts to? What I'm getting at is that you should be sure that you're not violating the Terms of Service by providing Web services to others (including email). If your company website has a number of email accounts, and you want to provide employees with more privacy and control over their emails, that would probably be allowed. A basic account isn't really set up to do such a thing. You might see if there is an email app you could run as part of your company site, where emails are forwarded into this app (or read by it) and the passwords in the app itself are controlled by the employees. You might also just forward all emails to outside accounts such as gmail. Just be careful if doing that to filter out spam that might cause gmail to block emails from your site (also preventing your customers on gmail from receiving emails from you!).

Ok thanks for your replies.