Here's some more words and abbreviations used on nicovideo, continued from my older post.
(gdgd) – An abbreviation for “guda guda” (ぐだぐだ), meaning something is messy or nonsense.
184 – Anonymous
(wktk) – An abbreviation for “wakuteka” (ワクテカ) which is, often ironically, used to express the fact that one “just can’t wait” for something to happen.
Wakotsu (わこつ or 枠乙 or 枠おつ) – Roughly means “Thank you for starting the broadcast,” usually said upon entry.
Upu (うｐ) – Upload; when you watch a video you can comment うpおつ, that means thanks for uploading.
Totsu Machi (凸待ち) – Waiting for a caller.
Shokunin (職人) – Comment artist.
Dokyun (DQN) – Term used in derogatory context describing individuals and groups with lower educational status. Someone who is lacking common sense or seen as violent/unruly.
Fudanshi (腐男子) - When a male likes yaoi.
Rom (ROM or ロム) – Looking at the broadcast without commenting, “Lurker”.
Niya Niya (2828 or ニヤニヤ) – Grinning/smiling.
Ikemen（イケメン） - Handsome, good looking.
Kotehan (コテハン) - Handle or screen name.
Kopipe (コピペ) – copypasta
Natsu Chuu (夏厨) – Someone who appears in the summer break and makes ridiculous posts.
Kuwashiku (kwsk or 詳しく) – give more detail.
Gaki (ガキ) - kid, brat.
Koe Mane (声真似) – Imitating a famous person’s voice.
Uta Waku (歌枠) – Singing broadcast.
Jichou (自重) – To respect oneself.
Hiwai (ひｙ or 卑猥) – Something (talk, acting of, etc.) sexual.
Pugyaa (m9 or プギャー) – An image of someone pointing a finger at you, the “9″ is the index finger, the “m” is the rest of the fingers, means “Look at yourself!”.
(KY) – An abbreviation for “kuuki yome” (空気読め), meaning ”read the atmosphere”.
Bouyomi-chan (棒読みちゃん) – Software that helps broadcaster to listen the comments without watching them.