1. Computer slang for "Amusement".
2. AMM (Amusement) is a very formal and controlled form of laughing and joy, used in moments where complete and utter geeks would type "LOL
3. An expression of amusement that diverts into the description of laughter; A movement (usually involuntary) of the muscles of the face, particularly of the lips, with a peculiar expression of the eyes, indicating merriment, satisfaction, or derision, and usually attended by a sonorous and interrupted expulsion of air from the lungs.
This conversation was pretty funny in my personal opinion, amm.