There's an article on Vault Hub that covers an interview with Jeff Anderson CEO of Turbine Entertainment. They talked breifly about a few facts that D&D Online will be to the player community.
Along with those tidbits Jeff did mention that they want to put the ORPG back into the MMORPG phrase. So those rats you've been fighting in one game as 3 foot monsters are now 3 inch rats that just infest your dungeon.
One last worthy phrase
"From the beginning, players will feel special. They won't be godlike, but they will feel they are different and hero-like. The game will have an epic storyline. He is a huge fan of periodic updates, although he wouldn't commit to having monthly updates in the game - he did say there will be updates and a live team committed to the project."
