@Bai SuzhenI'll share stuff related to gameplay, not plot.
There will be quests. These quests will be started in a separate threads, but linked to this one. Each quest will have objectives and a reward.
The objectives will be simple like, 'defeat so many bad guys' and 'each person must post X amount of times'. The reward will be hidden until the quest is cleared for the first time. The reward will be either a 'special item' or 'special ability'. These will give your character access to new areas or allow them to do extraordinary things.
To start a quest, each person will have to meet a certain level. The combined level of everyone questing together must also meet a minimum.
That's pretty much all you need to know about the leveling system and 'special abilities and items'.