I have to admit that I've never seen those, and I got the same association(??!!) as Bama about the former...IANAL = I am not a lawyer
IIRC = If I recall correctly
Yeah, I've seen that one, and it's really annoying, imnsho.XD is a smilie face, for people too lazy or whatever to use our REAL smilies.
IMNSHO = in my not so humble opinion
ETA: John snuck in right before me with some more ones, several of which I've never seen.
I missed ROFLMAO though, but I think you can guess what that one means .