Rheingold is a brilliant guy. I wonder though whether or not he has the same view of "virtual community" today that he had when he was writing about the WELL. In his new(er) book Smart Mobs he seems to "get" that virtual communities no longer need to be tied to a single "location" (website, etc) but instead typically cover many different sites which share a tightly woven structure of links back and forth to each other. Much as technology has served to remove the constraints of time and geography from communication in general, the few short years since The Virtual Community was published have seen a rise in the "distributed online community" -- basically a removal of the pseudo-geography of the web.
These distributed communities are essentially self-selected intersecting topic networks of sites. Each site remains entirely unique (and typically the brainchild of a single individual), yet becomes part of a greater whole as its author discusses various topics. It goes back to the idea of "user control." A site which requires you to be "on it" (like the WELL) affords its users less control than a distributed community does -- if for no reason other than the requirement of "being somewhere where other people are as well" has been lifted.