TINYF was an acronym for "Thaere Is Not Your Friend." The slogan was graffitied over the Cularin system and soon began appearing on badges and pins woren by the citizens of Cularin.
Sources
Thaere Is Not Your Friend on Wizards.com (original site is defunct) (First mentioned)
Destabilization on Wizards.com (original site is defunct) (As part of HoloNet userid)