Although Microsoft employees are internally assigned a cryptic email address by the IT department, the email address used for mail to and from the outside world is open to customization, to some degree.
For example, consider an imaginary employee named Christopher Columbus. Christopher might be assigned an email address like
ccolum or possibly the Slavic-sounding
chrco. But Christopher has the option of choosing the external email address: When he sends a message to somebody outside Microsoft, the "From" line will show the external address, and if somebody from outside Microsoft sends mail to the external address, it will get routed to Christopher.
When you choose your external name, you have a few options. The most basic version consists of your first and last name, separated with a dot:
Christopher.Columbus∂microsoft.com. You can include your middle name or initial, to distinguish you from other people who have the same name:
Christopher.Q.Columbus∂microsoft.com. There are other possibilities, like using your nickname or initials instead of your legal name, but that's the basic idea. There is one final option: Don't have separate external and internal email addresses; just use your internal email address for both.
I had a brief conversation with somebody who, as it happened, encountered a bug in the tool that lets you choose your external email address. This person wanted something fairly standard like
Robin.Williams∂microsoft.com but for reasons not worth going into since they're not important to the story, a bug in the system ended up assigning the external address
Robin.Robin∂microsoft.com. (Note: Not Robin's real name, so don't try sending to it.)
The IT department fixed the bug, but Robin decided to keep the erroneously-assigned email address. I'm somewhat jealous: It's not often that a database glitch ends up giving you a cool email address.