Information about the upcoming Age of Discovery expansion has been few and far between, however SmokeJumper did take a moment to clear up how XP and loot will work:
Actually, you earn XP *and* tokens. The tokens are used to acquire items for any of your characters, not just the one you have currently logged-in. XP and tokens are awarded at the end of the dungeon run and based on a challenge rating system that should prevent exploiting. More on this soon.
As we heard at Fan Faire (which may, of course, have changed since then) is that there will be two vendors for DYOD, one selling armor/weapons/loot for your main characters, and one selling parts to add cool stuff to your own dungeons.
No additional information has been released about what choices there will be for DYOD Avatars (since you cannot play your own characters, you must pick one of the provided avatars), if you’ll be able to buy upgrades for them, etc.