If you're new to internet forums, you probably have no idea what all these abreviations mean.
I'll start with a few, and please add to the list with as many as you can:
TTC - trying to conceive
DH - dear husband
LOL - laugh out loud (really loud)
lol - laugh out loud
MIL - mother-in-law
FIL - father-in-law
SIL - sister-in-law
BIL - brother-in-law
DGS - dear grandson
DGD - dear granddaughter
AF Aunt Flo (menstruation)
AFK Away from keyboard
BF Boyfriend
BIL Brother-in-law
BRB Be right back
BTDT Been there done that
BTW By the way
CTS Consider the source
DD Dear daughter
DH Dear (or darn) husband
DS Dear son
DSD Dear stepdaughter
DSS Dear stepson
DW Dear (or darn) wife
F/U Follow up
F2F Face-to-face
FAQ Frequently asked question
FIL Father-in-law
GF Girlfriend
HTH Hope that helps
IMO In my opinion
ISP Internet service provider
ITA I totally agree
J/K Just kidding
LOL Laugh out loud
MIL Mother-in-law
NP No problem
NT No text
OIC Oh I see
OMG Oh my gosh
OT Off topic
OTOH On the other hand
ROFL Rolling on the floor laughing
SAHD Stay-at-home dad
SAHM Stay-at-home mom
SIL Sister-in-law
SO Significant other
STBX Soon to be ex
TIA Thanks in advance
TMI Too much information
TTC Trying to conceive
TTFN Ta ta for now
TTYL Talk to you later
TY Thank you
URL Web page address
W/B Welcome back
W/O Without
WAHD Work-at-home dad
WAHM Work-at-home mom
WOHM Work-out-of-home mom
WTG Way to go
YW You're welcome
KWIM: Know What I Mean