PBEM is a much slower paced (typically a turn a week) Diplomacy, which can lead to more complex and indepth games. In addition, since they are adjudicated by a human GM, new maps and special rules can be implemented to make the game more dynamic and interesting. 

I am considering trying to boot up another game of NWO (New World Order, a coalition victory game with nukes) or Explore Dip (a Civilization type game where each player has to "explore" the map and everyone has their own map of what they can see, while also upgrading units and cities for bonuses). Alternatively, for more simple games, I might hit up just a map variant without too many special rules.
 
I'd love to get a mix of PBEM vets and new people to keep this game style active in our community. If you're interested in elevating your Dip to a new height and playing some of what might be the most fun Dip you've ever had, PM me!