There are a lot of mail servers out there. Microsoft Exchange has been the dominant corporate mail server in the enterprise on Windows, but I've been using Kerio Mailserver for a long time now and am still wondering if there aren't any better solutions.
Which mail-server do you use, and why?
What feature make a specific mail-server 'stand out'?
Both *NIX and Windows applications are welcome.
There usually is a lot to do about the security of servers since a lot of sensitive information is stored there but I think it's more important to make sure the company-laptops (and USB-Sticks) are secure since they're way easier to lose (or steal).
So what I want to know is: What does your company do to protect the confidential information on laptops and usb-drives?