Clasifications

[Alejandro]

I have seen this things many times and I dont understand what they do. Can someone please explain me what pokemon are the ubers, and what does ou, uu and stuff mean.

 

[.::Escalator::.]

Uber:
Mewtwo
Deoxys (All Forms)
Mew (Debatable)
Wobbuffet
Lati@s
And the Like

OU-Overused (Ex: Zapdos, Heracross, Metagross etc)
UU-Underused (Ex: Arcanine, Typhlosion, Altaria)
NU-Not Used (Ex: Hitmonchan, Luvdisc, Delibird etc)

This is determined by:
Stats
Movepool
Usability

 

[TRJessie579]

This GameFAQs page lists all of that with some nice explanations:

http://db.gamefaqs.com/portable/gbadvance/file/pokemon_frlg_moves.txt

You'll have to copy/paste the shortcut, since GameFAQs doesn't allow direct linking. Scroll down to "Pokemon Archetypes."

 

[SHUCKLE MAN]

There is also BL which means Borderline which is for Pokemon that can be useful in two categories or for Pokemon that are very hard to place, e.g. Blissey works well in OU and uber.

 

[intergalactic platypus]

Smogon has a detailed list http://www.smogon.com/community/showthread.php?t=1367
It may not be 100% accurate, but its the best guide for NB tiers you can find