What Does "ICYMI" Mean?

What Does "ICYMI" Mean? 

Nowadays, the hashtag # ICYMI is frequently seen on social media, and no doubt many people are curious as to what it means. Is it an acronym or is it an abbreviation? 
ICYMI is an abbreviation. ICYMI is a written abbreviation for "in case you missed it". 
There are many commonly used acronyms that you may not know. You may feel angry when you know what it means.

Some other common text abbreviations that intrigue you: 

AAAAA=American Association against Acronym Abuse. 
B2B = business to business.
BF = best friend or boyfriend.
BFF = best friends forever. 
BRB = be right back.
BTW = by the way.
FOMO = fear of missing out.
FWIW = for what it's worth.
FYI = for your information/waste of time/ignore it.
GIGO = garbage in, garbage out.
ICYMI = in case you missed it.
ILY = I love you.
IMO = in my opinion.
IMHO = in my humble or honest opinion.
IRL = in real life.
MSG = message.
NP = no problem.
OMG = oh my god.
TMI = too much information.
TTYL = talk to you later.
TX, THX or THKS = thanks.
TXT = text.
WTF = what the fuck
2nite = tonight
2day = today
2morrow = tomorrow
4U = For you
B4 = Before
4eva = forever
2hand = second hand