When sending email (in my case using the web front end) it would be great (a necessity in my case) to be able to chage the "From" address.
I manage multiple domains, but when sending mail through Zimbra, I can only send from one user/domain.
Other webmail solutions offer you a drop down box to list all your registered From addresses that you would want to use. Registration of these alternate From addresses in other mail solutions usually requires some form of authentication to avoid abuse - this authentication might come in the form of proof of domain ownership for example.
The lack of this feature (is it lacking or have I just missed it!!?) leaves me, and im sure many others, using rickety (non-ajax based) mail solutions such as runbox instead
