From:guildwars.com

Automated Tournament ladders for GvG and 1v1 will reactivate at Noon Pacific time (-8 GMT) on Friday, January 4, 2008. After the reactivation, combatants and guilds that have not played in a rated match for more than 90 days will be reverted to the rank "N/A" and removed from their respective ladders. Their rating points, however, will not be lost or changed. Once inactive guilds and players return and participate in a rated match, their ranks will return to the ladder positions warranted by their ratings.