AFAIK means "As far as I know"
AMA means "Ask me anything"
CMV means "Change my view"
DAE means "Does anybody else" or "Does anyone else"
•ELI5 means "Explain like I'm 5 (years old)"
FTFY means "Fixed that for you"
IAMA means "I am a"
IANAD means "I am not a doctor"
IANAL means "I am not a lawyer"
• IIRC means "If I recall correctly"
IMO/IMHO means "In my opinion" and "In my humble/honest opinion", respectively
ITT means "In this thread"
MRW/MFW means "My reaction when" and "My face when", respectively
NSFL means "Not safe for life" (gory or gross content)
NSFW means "Not safe for work" (sexual content)
OP means "Original poster" (the person who started the thread)
[Serious] means "Serious responses only" (commonly used in /r/askreddit and other subreddits now)
PSA means "Public service announcement"
TIL means "Today I learned"
TL;DR means "Too long; Didn't read
YSK means "You should know"