POPJ = P = post

poser n.

[from French `poseur'] A wannabee; not hacker slang, but used among crackers, phreaks and warez d00dz. Not as negative as lamer or leech. Probably derives from a similar usage among punk-rockers and metalheads, putting down those who "talk the talk but don't walk the walk".

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.