I know this is 5 months late but since no one answered.
SA = Same Anon (usually used in replies to one's self) OP = Original Poster (person who started the thread) AYRT = Anon You Replied To (used to indicate you're the previous poster, but didn't necessarily start the thread) NAYRT = Not [the] Anon You Replied to (used to indicate you didn't write the post the person you're replying to. Generally used if you have comments along the same view but don't want to seem like the same person, or if you want to share your own views on a subject the person brought up, but don't want to put words in the AYRT's mouth.) +1 or ^ or similar: expressing agreement (not sure if this counts but adding it here anyway)
Can't think of any others at this time, and I know I'm late enough you'll never see this, but oops.
Re: anonrerising acronyms
SA = Same Anon (usually used in replies to one's self)
OP = Original Poster (person who started the thread)
AYRT = Anon You Replied To (used to indicate you're the previous poster, but didn't necessarily start the thread)
NAYRT = Not [the] Anon You Replied to (used to indicate you didn't write the post the person you're replying to. Generally used if you have comments along the same view but don't want to seem like the same person, or if you want to share your own views on a subject the person brought up, but don't want to put words in the AYRT's mouth.)
+1 or ^ or similar: expressing agreement (not sure if this counts but adding it here anyway)
Can't think of any others at this time, and I know I'm late enough you'll never see this, but oops.