With belts, when you upgrade, do you get a few advantages, like faster movement and stuff? Or are belts just a way to say "lolol i'm better than uuuu"

No, belts are "medals", they don't give you special powers

Alright, thank you. It was just I saw a few 5th dans moving pretty fast. It looked alot like legit play, though, and not a hack. Also, had Minibash in my mind.

No, belt's don't give you superpowers. Although, I believe the Toribash Item Makers are going to implement Super Powers later on in a future update.

As a 5th dan I think he would know pretty much anything about the Tori, including how to make up for great momentum.
In other words, he knows how to move, fast.

The item forgers have announced a little "hint" regarding power-ups though, so might happen in the future ;o

http://forum.toribash.com/showthread.php?t=397629

Tori players just move the same as they are blaze

not even that.
they just exactly say how much matches u played in multiplayer. u can even get a QI boost which brings u 2 per match instead of 1. or u just buy the qi itself.
there are some items out which have QI requirments. like Pure, which needs 10k.

list of belts :
White Belt QI : 0
Yellow Belt QI : 20
Orange Belt QI : 50
Green Belt QI : 100
Blue Belt QI : 200
Brown Belt QI : 500
Black Belt QI : 1000
Black Belt 2nd Dan QI : 2000
Black belt 3rd Dan QI : 3000
Black Belt 4th Dan QI : 4000
Black Belt 5th Dan QI : 5000
Black Belt 6th Dan QI : 6000
Black Belt 7th Dan QI : 7000
Black Belt 8th Dan QI : 8000
Black Belt 9th Dan QI : 9000
Black Belt 10th Dan QI : 10.000
Master Belt QI: 15.000
Custom Belt QI: 20.000
God Belt QI: 50.000
One Belt QI: 100.000
Elite Belt QI: 1.000.000

highest reached is god belt by 3-4 players actually. (only one made it legally.)
also if u reach somewhere 3 mill qi it will reset to 0.

to reach elite belt u have to play some years.