I get asked about this frequently when new folks joined so I thought it would be a good thing to add to the library!!

AF/LF: Acid Free/Lignin Free
AFAICT: As Far As I Can Tell
AFAIK: As Far As I Know
AFK: Away From Keyboard
AI: As If!
AIUI: As I Understand It
ASAP: As Soon As Possible
ATM: At The Moment
AYPI: And Your Point Is
B2W: Back To Work
BAF: Brain Already Fried
BBL: Be Back Later
BBN: Bye Bye Now
BBS: Be Back Soon/Bulletin Board System
BCNU: Be Seeing You
BEG: Big Evil Grin
BF: Boy Friend
BFFL: Best Friends For Life
BFN: Bye For Now
BG: Big Grin
BH: Becky Higgins
BHG: Better Homes & Gardens Scrapbooks Etc.
BIL: Brother-In-Law
BOC: But Of Course
BRB: Be Right Back
Bsrgds: Best Regards
BTT: Bringing to The Top
BTU: Back To You
BTW: By The Way
BWK: Big Wet Kiss
BWL: Bursting With Laughter
C-I-S: Crop-In-Style
C&G: Chuckle and Grin
CBL: Come Back Later
CC: Core Composition or Credit Card
CH: Cropper Hopper
CK: Creating Keepsakes
CKU: Creating Keepsakes University
CM: Creative Memories
CMC: Creative Memories Consultant
CNP: Continued In Next Post
COI: Come On In
CSG: Chuckle Snicker Grin
CSS: Can't Stop Smiling
CTMH: Close To My Heart
CYA: See Ya
CYAL8R : See You Later
DB: Dear Boyfriend/Baby
DD: Dear Daughter
DE: Double-Entendre or Double Meaning
DF: Dear/Darn FiancÚ
DH: Dear/Darn husband
DLN: Don't Leave Now
DLTBBB: Don't Let The Bed Bugs Bite
DS: Dear Son
DTHT: Delighted To Hear That
DDWNUNR: Down Under
DOS: Dozing Off Soon
DTL: Deep Throaty Laugh
EG: Evil Grin
EMML: E-mail Me Later
EMSG: E-mail Message
F2F: Face To Face
FAQ: Frequently Asked Questions
FIL: Father-In-Law
FMN: Forget Me Not
FOAF: Friend Of A Friend
FT: Family Treasures
FWIW: For What It's Worth
FYI : For Your Information
GD&R: Grinning, Ducking & Running
GF: Girl Friend
GFN: Gone For Now
GMTA: Great Minds Think Alike
GPY: Grumpy
GR8: Great
GTG or GTO: Got To Go
GTSY: Glad To See You
GTTB: Gee, That's Too Bad
H&K: Hug and Kiss
HAGN: Have A Good Night
HF: Have Fun
HIG: How's it Going?
HMP: Help Me Please
HH: Holding Hands
HHIS: Hanging Head In Shame
HOF: Hall of Fame
HORU: How Old Are You?
HSN: Home Shopping Network
HTH: Hope This Helps
HTHS: Home This Helps Some
IC: I See
ICC: Ivy Cottage Creations
IDC: I Don't Care
IFF: If and only If
IGGNLTL: I Gotta Go Now, Let?s Talk Later
ILIC: I Laughed, I Cried
ILU: I Love You
INL: I'm Not Laughing
IMO: In My Opinion
IMHO: In My Humble/Honest Opinion
IMS: I Am Sorry
IRL: In Real Life
ISO: In Search Of
ISP: Internet Service Provider
ISTM: It Seems To Me
IWALU: I Will Always Love You
IWBS: I Was Being Stupid
IYD: In Your Dreams
JAS: Just A Second
JFG or J4G: Just For Grins
JK: Just Kidding!
JMO: Just My Opinion
JTLYK: Just To Let You Know
KHYF: Know How You Feel
KIS: Keep It Simple
KIT: Keep In Touch
KITSOTP: Kick In The Seat Of The Pants
KMA: Keeping Memories Alive
KOC: Kiss On Cheek
KWIM: Know What I Mean
L2SB: Love To Scrapbook
L8R: Later
L8R G8R: Later 'Gator
LAY: Looking At You
LB: Lisa Bearnson
LDD: La Dee Da
LLAL: Laughing Like A Lunatic
LHO: Laughing Head Off
LIS: Lost In Space
LMK: Let Me Know
LOA: Love On Arrival
LOIS: Laughing On the Inside
LOL: Laugh Out Loud/Lots of Love
LSHMBB: Laughing So Hard My Belly is Bouncing
LSHMBH: Laughing So Hard My Belly Hurts
LSOMCS: Laughing So Hard My Computer Is Shaking
LSS. Local scrapbook store
LTNS: Long Time No See
LUB: Laughing Under Breath
LUWAMH: Love You With All My Heart
LU4E&A: Love You For Ever And Always
LY: Love Ya
LYL: Love Ya Lots
LYLAS: Love You Like A Sister
MAMBI : me & my BIG ideas
MB: Message Board
MCC: My Creative Companion
MIASGB: Make It A Short Good-Bye
MIL: Mother-In-Law
MM: Memory Makers magazine
MPTY: More Power To You
MTFBWY: May The Force Be With You...
N2S: Needless 2 say
NE1: Anyone
NFT: No Further Text
NP: No Problem
NPNG: No Pain No Gain
NQWI: Not Quite With It
NSBR: Not Scrapbook Related
OIC: Oh, I See
OM: Old Man (husband, boyfriend)
OMKP: On My Knees Praying
ORN: Oh Really Now
OS: Off Subject
OT: Off Topic
OTTOMH: Off The Top of My Head
PDE: Puppy Dog Eyed
PDQ: Pretty Darn Quick
PG: Pretty Good
PK: PaperKuts
PLMK: Please Let Me Know
PLUR: Peace Love Unity Respect
PM: Private Message
PMP: Peeing/Peed My Pants
PMFJI: Pardon Me For Jumping In
POAHF: Put On A Happy Face
PP: page protectors /Paper Piecing
PPL: People
Paper Piecing Pattern
QT: Cutie
R: Are
ROTFL: Rolling On The Floor Laughing
ROTFLMHO: Rolling On The Floor Laughing My Head Off
ROFLUTS: Rolling On The Floor Laughing Unable to Speak
S^ Sup?: (What's up?)
S&N: Smile and Nod
SAS: Sobbing And Sniffing
SASE: Self-Addressed Stamped Envelope
SATH: Stay At Home Mom
SB: Scrapbook
SBing: Scrapbooking
SETE: Smiling Ear To Ear
SIAS: Scrap in a Snap
SIL: Sister/Son-In-Law
SJ: Stacey Julian
SO: Significant Other
SOS: Same Old Story/Someone Special
SOVS: Someone Very Special
SPWWYUT: Smile, People Wonder What You're Up To
SS: Secret Scrapper/So Sleepy
SSS: Secret Scrapper Swap
SSDD: Same Stuff? Different Day
ST: So There
SU: Stampin' Up
SWAK : Sealed With A Kiss
SWALK: Sealed With A Loving Kiss
SWL: Screaming With Laughter
SYDW2BY: See Ya, Don't Want 2 Be Ya!
SYITFP: See You In The Funny Papers
SYT: See You Tonight
SYS: See You Soon
TA: Thanks Again
TAN: Tangent
TBNT: Thanks But No Thanks
TEN 4: Read you clear
TFTT: Thanks For The Tip
TIA: Thanks In Advance
TNT: Till Next Time
TOY: Thinking Of You
TPTB: The Powers That Be
TT: Take That
TTFN: Ta Ta For Now
TTYL: Talk To you Later
TTYT: Talk To You Tomorrow
TVM: Thanks Very Much
TX: Thanks
U: You
UCCOM: You Can Count On Me
UR: You Are
VBG: Very Big Grin
W! or WR or WE: Whatever!
WB: Write Back or Welcome Back
WBASAP: Write Back As Soon As Possible
WBS: Write Back Soon
WDOI: Wouldn't Dream Of It
WGACA: What Goes Around Comes Around
WTG: Way To Go
WU: What's Up?
WAB: What A Bummer
WAUF: Where Are You From?
WDYLL: What Do You Look Like?
WGTG: Well, Got To Go
WH: What?s Happening
WOL: Win Or Lose
WRU: Who Are You?
WTH: What/Who The Heck
WTTC: Welcome To The Club
WTY: Waving To You
WYSIWYG: What You See Is What You Get
YBS: You'll Be Sorry
YGG: You Go, Girl!
YL: Young Lady