Common Japanese symbols punctuation

読点 : とうてん Tōten
Symbol ( 、)=> Comma mark - Instead of  symbol (,), Japanese language use this symbol instead.

句点 : くてん Kuten
Symbol (。) => Punctuation Mark - Instead of symbol (.), Japanese language use this symbol instead.

中黒 : なかぐろ Nakaguro
Symbol (・) => Interpunct - Used for separating Japanese words/titles/names or items to aid reading

鍵 ：かぎ Kagi
Symbol (「」) => Single quotation marks

二重鉤括弧 : にじゅうかぎかっこ Nijūkagikakko
Symbol (「...『...』...」) => Double quotation marks (to be only used within single quotation marks)

感嘆符 : かんたんふ Kantanfu
Symbol (! ) => Exclamation Mark - However, interesting enough, exclamation mark isn't common used in formal sentences as one thinks. They are usually used in casual writing, fiction and manga.

疑問符 : ぎもんふ Gimonfu or commonly known はてな Hatena
Symbol (？) => Question Mark - Another symbol that is not commonly used in formal sentences but commonly used in casual writing, fiction and manga.

濁点 : だくてん Dakuten or commonly known as てんてん tenten
Symbol (゛) => Used with both hiragana and katakana to indicate a voiced sound. For example, ta (た) becomes da (だ), shi (し) becomes ji (じ). For full list of dakuten wordings, please refer to hiragana and katakana list

半濁点 : はんだくてん Handakuten or commonly known as ○・丸 maru
Symbol (゜) => Used with hiragana and katakana to indicate a change from a ha hi fu he ho sound to a pa pi pu pe po sound.

同の字点 : どうのじてん Dō no jiten or commonly known ノマ Noma
Symbol (々) => Kanji repetition mark.

郵便 : ゆうびんYuubin
Symbol (〒) => Postal sign used in Japan

Extracted from:
http://en.wikipedia.org/wiki/Japanese_typographic_symbols
http://en.wikipedia.org/wiki/Japanese_punctuation