Yes! All of our servers that contain and pass private
information are secured by various means, including 256-bit public
(ssl) certificates. You'll notice the https and the lock in your web browser on our web sites, which means the sites are secure:

Some examples of our sites that are secure include your web mail, your domain admin, your spam and virus admin, your billing manager, your help desk, and your order forms.
We also keep our servers physically in a high security environment,
inside a data center protected by 24/7 live and video camera
surveillance, biometric handscanner with identification code, and then
inside locked cabinets. When it comes to data security, we also make
daily back-ups, see our SLA for more info.
Note that not only do we use HTTPS, 256-bit public
SSL for our web services, but also for our sync sessions, IMAP, POP and
SMTP, so your passwords and sessions are encrypted. You have the option
to use unencrypted services, too.