on various message boards you can PM or "Private Message" someone

Private Message

PM, Pm, pm or p.m. can refer to: Time. Post meridiem (also written P.M., p.m., and pm), "after noon" in the 12-hour clock, in contrast to ante meridiem (a.m., "before noon")

1. a personal or private message

2. to send someone a personal or private message on a message board, forum or chat room

1. premenstrual syndrome-PMS A varied group of physical and psychological symptoms, including abdominal bloating, breast tenderness, headache, fatigue, irritability, anxiety, and depression, that occur from 2 to 7 days before the onset of menstruation and cease shortly after menses begins.
2. a school in canada (Pitt Meadow School..seriously it does REALLY exist!)
3. a natural situation when a girl have their period and they become bitchy and become sharp (same as #1 but alittle different)

A Prostate Massage

A ruthless gang who patrol the South of England jumping various other, more minor gangs. It is believed that the PM originally consisted of only five founding members, and have grown to be feared ever since.