The firms that get it right are the ones who stand aside. My definition of social media helps to clarify the role of companies in the process:
Social Media is all about making tools available to enable and track conversations about your brand or product.
These conversations are already going on. If you want to be the fly on the wall, you provide some vehicle, some nifty little tool or some cool new site that allows users to have these conversations more easily, and you follow the discussion.
You don't market your product, you don't smack down or erase negative comments. You let it happen naturally. That's when customers will be themselves and will be more likely to trust your brand.