PM

From SA Mafia Wiki

A PM is a private message sent on SomethingAwful. You must have the platinum upgrade to receive and send private messages. Players who have platinum prefer to receive their roles via PM, as the forums will save all messages until you delete them so it makes it easier for the player to go back and check their role. Most mods have PMs as well, and a few even exclusively only send role PMs to players with platinum due to the hassle of emails.

The Platinum upgrade costs $10 USD.