Well for starters, it's easy to remember and easy to spell…
As Erasmus points out in "In Praise of Folly," we sometimes spend so much time worrying about whether or not we will look foolish to others that we wind up not doing what we really want to. And that itself is pretty foolish. When I think back on all the things I didn't do because I was afraid of looking foolish, I feel very much the fool.
In "Care of the Soul", Thomas Moore points out that friendships are seldom made at the lofty heights of intellectualism. Rather, most friendships are cemented with being able to laugh and be silly together. The e-mail address provides me with a little reminder to loosen up and not take myself too seriously.
The book "Jung and Tarot" contributes "the Fool is a good character to consult whenever we find that our best-laid plans have gone askew, leaving us hopelessly adrift. At these times, if we listen we can hear him say with a shrug, he who has no fixed goal can never lose his way." Ironically enough, that was precisely the state I was at when I chose this e-mail address. Perhaps it really is a universal archetype.