Hmm... I'm wrong on thinking that "JP" is an acronym for "Japanese Player".
I just looked it up at: http://www.hmx-12.net/~virgil7/netEchat/commu_ffxi_3.htm#G
As for "NA", JP players use ŠOl but I use
‰pŒê”ŃvƒŒƒCƒ„[ [English Version Player]. *Shrugs* I get asked why I use this a lot... I simply in Japanese text say
ŠOl‚Í‚Ü‚±‚Æ‚É•ÌÌ‚Å‚·B‚»‚ê‚ÉŠO‘lƒvƒŒƒCƒ„[‚Í–k•Äl‹–‚è
‚Å‚È‚A‚½‚‚³‚ñ‚Ì–k•Ä”ŃvƒŒƒCƒ„[‚Í–k‚Ì•ÄŠO‚ÉZ‚ñ‚Å‚¢‚é
—Ⴆ‚Ή¢ˆŸ‚Å‚·‚æB >_> <_<
As for gilfarmers, ’†‰Ø [(Mainland) China] is used instead.