Threads worthy enough to become a sticky are generally determined by a forum moderator.
In the VMK Forum on DIS, generally the threads that become stickies are ones that provide information key to playing a game; for example, a players guide, code lists, furniture guides, pins guides, etc to name a few.
Other stickies benefit the community. One in particualr is the teleporter network sticky; that became a sticky because it is a valuable resource to the community in the game to meet other DIS'ers and provide a common place to hang out. Another is the VMK name sticky; that helps us recognize the DIS'ers and their virtual conterparts!
As far as forum use : All FAQ's regarding the "how to use", "how to post" and the like, those are usually in the main DIS forum menu or UserCP and not on the VMK forum.
BTW: I believe your question relates to the Airlock Escape Guide and why that is not a sticky. If you look in the Players guide, a link to that thread is already there.