His middle name is James (Jimmy)...

[cureformax]

...I just realized that. I figure that he wouldn't be called Maynard in school (its tough having a wierd name when you are young -- I should know, I was a Max before everybody's goddamn dog was named Max) so James or Jimmy would work. Meh...

[Sandoz]

Maynard isn't a weird name.

And.... Duh.

[h...]

Actually, his birth name is James Herbert Keenan, but he changed it to Maynard James Keenan. So in school, he probably was called Jimmy since James was his first name.

[GAiDEN-CHaKRa]

his birth name was James Keenan. Maynard was never even a part of it. im guessing he added it so he didnt have a common name. And its not weird, i've seen a maynard in the phonebook. and yes a lot of people have figured that the song is about keenan as a boy.