'Senpai, I suppose, were newbies once.'
A fact: fans tend to refer to their series by shortforms. It can be very confusing until you get used to it, so here's a list of some of the more common series acronyms. Note that these are the forms I've seen them in. There may well be others. Not all of the fandoms listed are anime or even Japanese, but with one or two exceptions, all the Japanese series have pages listed on the Anime Web Turnpike. Go to that marvellous source for more info. (Note: the turnpike doesn't always indicate long Japanese vowels in a title. To avoid confusion I've written the title as it appears there.)
With any luck, there'll be a subsequent list of RPG (role playing game) shortforms in future. CC, KoF, VS. Like that.
AnC- Ayashi no Ceres
AnK- Ai no Kusabi
AS- Angel Sanctuary
BF- Bananafish
BH- Bakuretsu Hunter
BotI- Blade of the Immortal
B'tX- B'tX, oddly enough
CCD- Clamp Campus Detectives
CCS- Card Captor Sakura
DBZ- DragonBall Z
DnA- D.N.Angel
FotR- Fellowship of the Ring
Furuba- Furutsu Basketto- Fruit Basket
FY- Fushigi Yuugi
GSM- Ghost Sweeper Mikami
GTO- Great Teacher Onizuka
GW- Gundam Wing
HanaDan- Hana yori Dango
Hanakimi- Hana Zakari no Kimi tachi e
Harudaki- Haru wo Daite ita- manga series by NITTA Youka
HE- Hoshin Engi
HnG- Hikaru no Go
HnM- Honoo no Mirage/ Mirage of Blaze
HP- Harry Potter
HxH- Hunter x Hunter
IniD- Initial D
IY- Inuyasha
Kare-kano- Kareshi Kanojo no Jijou/ His and her circumstances
KKH- Kusatta Kyoshi no Hoteishiki
KKJ- Kamikaze Kaitoh Jeanne
KtKnU- Kaze to Ki no Uta- shounen ai manga by Takamiya Keiko
LH- Love Hina
LM- Love Mode
LoGH- Legend of Galactic Heroes
LotR- Lord of the Rings
MB- Marmalade Boy
MTT- Mahou Tsukai Tai
OP- One Piece
PoT- Prince of Tennis
PSME- Please Save My Earth
PSoH- Petshop of Horrors
RGV- RG Veda
RK- Rurouni Kenshin
RoV- Rose of Versailles aka 'berubara'
SD- Slam Dunk
SK- Shaman King
SKU- Shoujo Kakumei Utena
SM- Sailor Moon
StS- St. Seiya
ST- Sakura Taisen/ Star Trek
SV- Smallville
SW- Star Wars
TB- Tokyo Babylon
TS- Twin Signal
WE- West End- manga by AOI Futaba and KURENAI Mitsuba
WK- Weiss Kreuz
YnM- Yami no Matsuei
YST- Yoroiden Samurai Troopers aka Ronin Warriors
YYH- Yuu Yuu Hakusho