Do you know ghouls from goblins and ghosts?
1. [Usenet] Read The Manual. Politer variant of RTFM.
2. Robert T. Morris Jr.
The perpetrator of the great Internet worm of 1988 (see Great Worm); villain to many, naive hacker gone wrong to a few. Morris claimed that the worm that brought the Internet to its knees was a benign experiment that got out of control as the result of a coding error. After the storm of negative publicity that followed this blunder, Morris's user name on ITS was hacked from RTM to RTFM.