Okay some basic information. I am an Alpha tester for this game so I can't give any direct specifics due to the NDA which is even tighter than beta:
The game began life as a co-op game that was bought out and turned into an MMO by Cryptic/Perfect World entertainment.
It is based off of 4E rules, 4E being VERY differant from previous versions of D&D. For example there is no spell memorization, or anything of that sort. Rather characters are given abillities defined as "at will", "encounter", or "daily" depending on how often they can use them. A mage in 4E for example who knows magic missle can spam it every time he can attack (like a weapon) since it's an "at will" power. More powerful abillities are defined as being things you can only use so many times per each "step" in an adventure deemed an encounter, or daily which given the lack of down time for memorization means infrequently, or once before a rest period (or perhaps even just once in an adventure).
On their forums it's been mentioned that in game terms this amounts to a situation where your at will abillities are ones you can spam, encounter abillities have a cooldown much like abillities like you'd expect from a wow-type game, and he daily powers work on their own system which I don't know if it's been revealed yet.
As far as Cryptic/Perfect World's business model goes, I have mixed opinions. To be honest the one big selling point on them is that they let you trade in-game currency, for real-money currency, meaning that if you play long enough everything in the cash shop can in theory be obtained without spending a dime. That said however the point is still to make things a lot easier by spending money, and that's understandable as these games do need to support themselves. I prefer a subscription system, but apparently the FTP model is dominating, and at least this way of doing things has the doors open to an extent. I find the expectation that people have that a large scale game project, requiring servers to be maintained and administrated, and involving occasional content additions, an be provided in it's entirety entirely free of charge kind of silly. It would be nice if that could happen, and while I seriously slam the games industry for being greedy, I also think it's equally dumb to have people complaining about video games of any sort not being
entirely free. Obviously, any game you play is going to have some way of trying to get you to pay money into it. I play both CO, and STO (lifetimer to both) incidently.
At any rate, this said, I won't put up any more until later in the process, including even an opinion as to whether it's a good game, or liable to be successful (I'm actually a pretty good judge of that) or not so far. This should answer a few of the most basic questions though.
The big point to consider here though is that as 4E is nothing like 3E/3.5E, never mind the golden age of 2E, or the editions that came before it, you can't compare this at all to other D&D computer games. If you expect this to be like NWN / NWN2 except online and persistant (perhaps like an updated version of the game, with someone's personal module developed to the point of being a full game world), you are going to be disappointed, the mechanics it's based on alone are pretty bloody differant.
Also they kind of blew up most of Forgotten Realms as of 4E, to a greater extent than they did with "The Time Of Troubles" or "The Threat From The Sea" that heralded 2E and 3E changes respectively. Numerous gods were revealed to simply be aspects of other gods and re-absorbed, many more were killed, the entire nature of the cosmology has changed, Tieflings for example are defined as being a playable race and coming from some ancient empire that had fallen and was always allegedly there, as opposed to being truely "planetouched" which no longer really exists.... and tons of other stuff. If your familiar with 4E at all and how the new cosmology and such works, it's a LOT simpler, but at the same time kind of an insult to The Realms, and Realmslore that came before since they pretty much took a eraser to the thing when Abeir merged into Toril. Probably some businessman's idea on how to make it more approchable to new gamers or whatever.
Let's just say that if you know 4E FR... it's probably not the world many people who played previous editions of the game remember. Speaking of the lore/world before you ever get into the MMO. It's also why you'll notice things like "Tiefling" being a race on the main website, since they are now defined as being a "core" race rather than the
rare result of infernal breeding.