An 31337 Education

Overheard:
 My niece Lani asked her cousin for Uncle Mark's email address.

Caroline: It's Mark underscore Morris.  Do you know what an underscore is?
Lani: (indignantly) Of course I do.  It's that little line like a dash, only it's at the bottom.  You have to press the shift key to make it.
Caroline: OK, want to play pretend?
Lani: Sure, what should we play?
Caroline: Let's be little girls who live in a mobile home.
Lani: What's a mobile home?

By the way, Lani didn't write down the email address.  My guess is, she didn't need to.  How hard is it to remember Mark underscore Morris at Yahoo?  Not hard at all, if you're 1337.