http://aa.2ch.net/mona/kako/1024/10241/1024144855.html

ITT we study the characteristics, origins, etc. of all the various 2channel AA characters!

See here http://www.blogjam.com/index.php?p=000948
and here http://shii.org/2chgrounds/faq
and here http://aa.2ch.net/mona/kako/1024/10241/1024144855.html
and here http://aa5.2ch.net/test/read.cgi/aasaloon/1081639199/
and here http://members.at.infoseek.co.jp/maruheso/aadic/index.html

Moralar=Mattarly
　　 ∧＿∧　　　／￣￣￣￣
　　（　・∀・）　＜　Loosen up! Please.
　　（　　　　） 　　＼＿＿＿＿　Don't disorder the conduct of BBS!
　　｜ ｜　|
　　（_＿）＿)

Giko's favorite phrase is "ITTEYOSHI!!"

　　＿＿__＿∧∧　　 ／￣￣￣￣￣￣￣
〜'　＿＿__（　ﾟДﾟ）＜　　逝ってよし！！
　 ＵU 　 　Ｕ U　　　 ＼＿＿＿＿＿＿＿

This often gets translated as with "Go and die" or "Kill yourself" or "Fuck off". All of these translations seem to be not getting the jist of the expression, though, since "Itteyoshi" is a play on words: http://4-ch.net/nihongo/kareha.pl/1101446156/55

> If you're a japanese and hear it without seeing the chinese character used in it,
> then you will think it means "you may go" ,or "go away" in a less dominant imperative.
> But if you read it while seeing the chinese character,
> it means "you may kill yourself" or "kill yourself".
>
> You can use this phrase when someone posts a silly remark or
> asserts something with lame evidence.
>
> note: "行く(iku)" means "to go", "逝く(iku)" means "to die".

　　　　　　　　　　　　　　　　＼　│　／
　　　　　　　　　　　　　　　　　／￣＼　　 ／￣￣￣￣￣￣￣￣￣
　　　　　　　　　　　　　　　─（ ﾟ ∀ ﾟ ）＜　SAITAMASAITAMA！
　　　　　　　　　　　　　　　　　＼＿／　　 ＼＿＿＿＿＿＿＿＿＿
　　　　　　　　　　　　　　　　／　│　＼
　　　　　　　　　　　　　　　　　　　 ∩ ∧　∧　　／￣￣￣￣￣￣￣￣￣￣
￣￣￣￣￣￣￣￣＼∩ ∧　∧　＼（ ﾟ∀ﾟ）＜ SaitamaSaitamaSaitama！
Saitamaaaaaaa！ 　 ＞（ ﾟ∀ﾟ ）/ ｜　　　　/　＼＿＿＿＿＿＿＿＿＿＿
＿＿＿＿＿＿＿＿／ ｜　　　 〈　｜　　　｜
　　　　　　　　　　　　　 /　／＼_」　/　／＼」
　　　　　　　　　　　　　 ￣　　　　 / ／

Originates from a logo of the Liberal Democratic Party of Japan:

http://web.archive.org/web/20021018125339/http://www.jimin.jp/jimin/jimin/t_rogo.html

Soon after this logo became known, AA were created for the "Liberal-Democratic Monar Party"

There are various theories as to why the characters have begun shouting SAITAMA without an end:
http://members.at.infoseek.co.jp/maruheso/aadic/sa.html#saitama

But as Saitama, a prefecture in Japan (and also the name of its capital city), is known for funny news coming from it, the enthusiasm expressed by these cute little fellas can easily be understood.