Frylock
Explorer
Have you read the accompanying FAQ? I quoted various bits of it above. What WotC wants is made abundantly clear there in plain English: they want you to discuss your playtest experiences publicly anywhere you wish. They say that explicitly, so there's no doubt as to what they want.
Whether the EULA (which is what it resembles more than anything else) accomplishes that effectively is arguable, but their intention is pretty clear.
Yes, I read their FAQ, and my first draft of the article discussed it. I removed it because a FAQ can't override an enforceable contract. Reliance on it is often misguided unless the contract is unenforceable. However, it's certainly relevant to someone coming from my point of view. Let's assume it's relevant. Here are some interesting quotes.
DnDNext FAQ said:How will I provide feedback on the playtest materials?
You will periodically receive links via the email address you provide for your Wizards.com account to take surveys about the playtest materials. Just answer the survey questions and hit “submit”. You can also provide feedback through polls contained in many online articles discussing D&D Next. Look for playtest-related articles on DNDNext.com.
So, it appears "feedback" (whatever that means) can be provided, and the means for which is spelled out: Either "respond to our surveys or answer our polls in our online articles." In other words, "feedback" is to be limited to official WotC channels.
DnDNext FAQ said:Can we run this playtest at home or is it only in stores, like D&D Encounters or D&D Lair Assault?
You are welcome to run the D&D Next playtest at home. However, all members of the group must follow the official sign-up process at DNDNext.com and agree to the terms and conditions for playtesting.
Ahem.

DnDNext FAQ said:Where can I go to talk to others who are playtesting? Is there a forum or discussion area?
Feel free to discuss your thoughts about your D&D Next playtest experience anywhere. We have also created a dedicated D&D Next playtesting forum on our community site located here: community.wizards.com/dndnext which is a great place to connect with other playtesters.
So yes, according to the FAQ, it's clear WotC doesn't mind you using ENWorld "to discuss your thoughts about your D&D Next playtest experience." Is that different from "feedback"? Maybe. "Feedback" could include things that WotC wants you to keep confidential, such as game rules otherwise not protectable, but perhaps also the content and format of stat blocks, the classes and races included, etc. Your "thoughts" might be restricted to high level, obscure statements like, "Gee, I really like this D&D Next stuff." On the other hand, feedback could simply refer to your "thoughts" when they're expressed to WotC developers directly; however, that would still leave a gaping hole as to what's to be kept confidential, and the FAQ is silent on confidentiality. So, without a clear definition provided by WotC themselves, that leaves things a little difficult to interpret, and a judge would interpret them against WotC (again, assuming a judge would even consider the FAQ).
But now I'm getting to bogged down in legalese again. No one's getting sued. The point is that WotC has made the following statement: They want you to keep things in confidence while publicly discussing whatever you want about those things. I'm trying to interpret that ridiculous statement, resolving the paradox it creates as reasonably as possible, and WotC isn't helping me in the effort.
I understand your interest in interpreting that statement to allow your forum users' right to discuss everything here (excepting copyright infringement, of course), and for now, you're probably right because of the ambiguity and questionable enforceability of the confidentiality clause. However, you should understand that I'm addressing a question that's a bit larger in scope than that, and I suspect WotC might clarify their position in the future. When and if that happens, then we might have to watch our step.