In Silithus, the objective revolves around collecting dust, called "silithyst," and players will activate the geysers to collect the silithysts. You get a nice "buff" (stat boost) when you turn in the resources, but you'll be flagged as a PvP player as soon as you pick the stuff up, making you attackable by anyone in the opposing faction while you attempt to make your way back the Field Duty camps associated with the Cenarion Hold faction quests. If you manage to turn in enough of the dust, all of your fellow faction members in the zone will gain a buff as well, including those in the "AQ20" Ahn'Qiraj dungeon.