Answer: lurker

AnswerCrossword Clue
LURKER

Passive reader on line

LURKER

Online newsgroup non-participant

LURKER

Shy chat room participant

LURKER
Person who reads online but doesn't comment
LURKER
Shadowy
LURKERChat-room nonparticipant
LURKERProwler.
LURKERSneak
LURKEROne who skulks
LURKERFurtive sort
LURKERChat room nonparticipant
LURKERSkulker
LURKEROne who prowls
LURKERHe's sneaky
LURKEROne who reads but doesn't contribute