Do Virtual Worlds Bring Us Close Enough for Activism?

I was just reading an article about Marshall Ganz's work with the Sierra Club. Here's a snippet:

"The one effort that stands out most in successfully engaging these people and prompting them to take active roles in their chapter or group are new member meetings. Personally meeting and creating relationships with new members makes them more likely to become an activist."
http://www.sierrasummit2005.org/sierrasummit/coverage/r076.asp

Do virtual worlds or social networks bring us close enough to meeting in person to serve the same social function? My thought is 'no' - at the present - that a Second Life encounter is not enough like meeting in person. But could it be? What if the avatars looked exactly like real people? What would it take to deliver enough of a sense of reality to provide the same type of social reinforcement that exists in an in-person meetup?  Psychologically, what  does Second Life or hanging out on Facebook not provide?

Maybe FB is as close as we get to real world experience right now b/c of its culture of authentic identity. What if FB had a virtual world component? Would that make the experience of meeting any more lifelike and therefore more encouraging to activists? Causes drives some degree of peer-pressured activism, but it can't match peering into someone's eyes while committing to support a cause.