Entroper on 14 June 2007
I think "estimate" means that you are approximating something based on some information that you have, while "guesstimate" means you just pulled it out of your ass.
Don't get so pissed off, Alex. :)
EDIT: "Would of" instead of "would have." Just say "would've" if you want to say it the way it sounds in your head, at least you'll be right.
