If an eCommerce site's forums are used properly... meaning not to figure out how to spam around the net to get the word out, not begging for sales, not running buying contests for points, not running listing contests... they can be incredibly helpful. I never would have learned how to sell regardless of my price on Amazon without watching and talking on the seller's forum.
I post daily on several forums connected to my venues to help new sellers (yes, my competition, the HORROR!) and in turn receive answers to my questions quickly as well. Someone starts to cause a ruckus on a forum, they are banned from the forum regardless of their "standing" in the community.
I watched a 3 year seller get banned from Overstock auctions because of a nasty comment he made about the site's unstated policy about handbags. After he was warned, he didn't comply and is gone. That is the type of social activity I appreciate on an eCommerce forum.
eBay certainly polices their forums. There are millions of members, and eBay is responsible for anything on the forums. A site like Bonanzle (which appears to be one of the sites in the article by the "seller called chat window auctions" section) though, polices the wrong members. Just because someone is paying they may receive a little leniency over a free member. That's their perogative. I've only had about 20 sales on Bonanzle myself in a year, which is still more than many who post many times daily in the forums. I won't, however, chat it up in the forum begging for sales. It costs me nothing, only took a couple hours to import the listings, but if I get entangled in the web I will make enemies... it's my nature to question things someplace like Bonanzle.
Social aspects of selling are fine. I loved it on eBay, and talked every day in my regular forums and my eBay group I created for trading assistants in my state. But there are limits. I never had a sale from there, and never will expect one, so I don't worry too much with what folks there think of me.
Truthfully, if my Wagglepop memory serves me correctly, only about 50 or so sellers posted at the peak of Wagglepop's store count. If that holds true, then I will assume that about 5-10% of members at every site actually use the forums and place stock in what is said there. That leaves the whole 90% of the site that doesn't really care, and will shop with you regardless of what you say in the forum.