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Twitter, on account of the 140 character limit so most of us using Shorthand typing there. And also using Acronyms there to type the message. Here is a list of Acronyms that people deem more specific to the Twitter “dialect”.
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@ – Reply to [username]
bt – About
AFAIK – As Far as Know
bgd – Background
b/c – Because
b4 – Before
bst – Best
BR – Best Regards
BTW – Bu the Way
BFN – Bye For now
DM – Direct Message
chk – Check
clk – Click
EM – Email
EMA – Email Address
fav – Favorite
FB – Facebook
FTL – For The Loss
IRL – In Real Life
JV - Joint Venture
J/K – Just Kidding
LMK – Let Me Know
OH – OverHead
PRT – Partial Retweet
RT – Retweet
YMMV – Your mileage may vary
YW – Your Welcome
good list