The creatures from Dal Quor and Xoriat that haven't entered Eberron for millenia have found a new entrance in Eberron's Shadow as Dark Cthulhuian Gods older than them all have begun to awaken and weaken it.
A dynamic setting built around the core concepts of D&D; bold knights, great heroes, cunning rogues, foul monsters, lost treasure, poweful magic, and lots and lots of dragons.
"The Crazy Setting Where I Experiment All My Crazy Ideas About D&D Metaphysics, Racial Interactions, And Rule Design!"
I could give several one-sentence descriptions that were true at one time or another, but aren't accurate anymore. Because at its core, it's the above.
Right now, I could redact it that way: "A world where places and locales are alive and have feelings, a world once cleft in twain by the gods, and since torn apart by senseless wars, hatred and other base instincts as fiends gnaw on the planet from the inside like a cancerous parasite and extraplanar threats conspire to destroy it before the fiendworld comes to term, so you can see that heroes have a lot of work to do."