The uncertain world

Search google for the word definitely and you get 92,800,000 hits, search for probably and you get 307,000,000, over 3 times as many.
I wonder why that is; are people just not sure about things? or are they just non-committal.
My theory is that it's the nature of the web, people like to disagree and have their voice heard so if you say something that isn't 100 % correct then people love to correct you. So saying probably gives you a way out.

I would just like to say that my theory is definitely right.