If you really want to know, here's how it works.
It assigns each letter in your name a number a=1, b=2, c=3...etc.
Then it adds up the numbers and gives you the name assigned to that sum.
So a name of a,b gives you the same nickname as a,aa or c,<blank>
Some funny ones i saw were "Ghandi Mangler" and "The Self-Toucher"