We check the HTTP_REFER (when that option is ON) to make sure that the post or action called came from your board and not from a form someone setup on another website. It is not tracked, it is not kept in the database, it is not stored. You can turn it off in the admin area if you as an admin are not comfortable withj this check.
This OpenTopic board is built on entirely different architecture and we can use other means to check where you are posting from.
Honor The Victims
