Deprecated abbreviation for Alan Cameron Wills (if you mean the UK guy who used to be an OO consultant and now hangs around in Microsoft).
In past times (in Europe, roughly the Middle Ages), people felt the need for a second name most acutely when they started travelling around more. Similarly, when I discovered how many people share my first and last names, I decided to start using the middle one for work purposes.
See original on c2.com 