I think it's fairly common to see "forum junkies" on more than one. Especially in a case like this, where both companies are after the same type of customer, in terms of green ideal and wealth. Checking in on another forum is also a good source of info from the "other side" so to speak.
Personally I find marque-specific forums to be the best sources of info, as they collect from myriad other sources and present the most relevant and current. Plus the most hard-core types are frequently "connected" and can have insider info. Sure beats using Google in vain to find the latest news.
As an enthusiast I find myself most frequently on forums that do not apply to cars I own! They are the most interesting (Spyker, Koenigsegg, Pagani). I come here mostly for news on the burgeoning electric car movement, and to see what's up with Tesla. It's a fascinating story.
I also have a login on FiskerBuzz, but to be honest I don't go there very often. It was more fun when everyone was speculating when the Karma was finally going to get here, and they were all worked up! Once the car was finally here it was interesting watching all the problems that everyone was having, but it quickly became clear that the majority of the users only wanted to see things through rose-colored glasses, and anybody with a (valid) dissenting position was vilified. So my desire to spend time there waned quite a bit. It's purely a fan site, not an open forum.
I would be careful if I ran this forum. For example I've seen a some comments about problems with the Model S or concerns about the company and their ability to deliver. Very quickly these positions are stomped down, people are told what they should be thinking, or moved to "snippiness". I find that a dissenting opinion here is not always welcome. If one really wants honest and open discussions then one should be willing to accept the occasional contrary comment; it's the foundation of this country. Otherwise all you have is a rah-rah fansite, which quickly loses credibility.
In my view, that's what happened to FiskerBuzz; don't let it happen here.
Just my $.02, not that anybody asked.