1. What Do You Mean? Jargon used for simplifying text-based interactions between two or more people, used in a way similar to the more popular "lol" "rofl" and "wtf."
2. World Defining Yore-based Machine. A fictional device created by lesser-known author Francine Gaffigan (of Iowa), as a reference and alleged homage to Rube Goldberg, the man behind the concept known as the "Rube Goldberg Device
The WDYM, in short, was a shopping-mall sized machine which would somehow gather the latent energy in every dream by every man, woman, and child within a 5 mile radius, which would then be used as a cleaner, safer version of more conventional power plants. This energy would then be used to power an exceptionally large virtual game world which would be based partially on the ideas encoded within the captured dream energy.