Hooked Games has put together their own preview of Dungeons & Dragons Online: Stormreach, which looks to be based on their time within the game's ongoing beta test. A little something to get you started:
Adventuring is the only way to gain experience in Dungeons and Dragons Online, and this is not in the form of running out to the closest monster and "grinding" your way to 10. Guess what, no dice, you only gain experience through "completed" missions! That level cap seems a bit further away now doesn't it? In addition, Dungeons and Dragons Online is not solo friendly, much like the real Dungeons and Dragons, it is unlikely you will survive even the easiest dungeon or mission by yourself. Dungeons and Dragons Online holds very close to the mechanical system of 3.5, therefore, it is unforgiving. Mages will only take a hit or two at first level because they only have 4 to 6 HPs. Dungeons and Dragons Online is built for groups, it is a social game, if you like to play MMO's the solo way, you will be extremely disappointed and aggravated.