1) Be about 2) Be like a sneaker 3) Browse without comment 4) Conceal 5) Creep 6) Emulate a newsgroup newbie 7) Hang about 8) Hang about menacingly 9) Hang around 10) Hang around in the shadows 11) Hang around unobserved 12) Hang around unseen 13) Hide 14) Hide and sneak 15) Hide furtively 16) Hide in ambush 1) Bushwhack 2) Footle 3) Hide 4) Lallygag 5) Loiter 6) Lollygag 7) Prowl 8) Skulk 9) Stalk 10) Wait 11) Waylay 
• (v. i.) To lie hid; to lie in wait. • (v. i.) To keep out of sight.
Listening to a newsgroup or mailing list without posting
to observe the activities in a computer conference passively and without becoming noticeable
Lurk (lûrk) intransitive verb [ imperfect & past participle Lurked (lûrkt); present participle & verbal noun Lurking .] [ Middle English lurken , lorken , probably a dim. from the source of English lower to frown. ...
Scheme (no negative connotation). 
be out of view ready to attack 
Lurk is Australian and New Zealand slang for a scheme or stratagem for success.
[v] - lie in wait, lie in ambush, behave in a sneaky and secretive manner
Scheme, sometimes viewed with envy
verb lie in wait, lie in ambush, behave in a sneaky and secretive manner
to lie or wait in concealment, as a person in ambush; remain in or around a place secretly or furtively. · to go furtively; slink; steal. · to exist unperceived or unsuspected. · to observe an ongoing discussion without participating in it.
illegal or underhanded racket
[SAT terms] lie in wait or behave in a sneaky and secretive manner