Mario pointed me to a very "bullish" article about meetup.com.

"The Next eBay. That's what Pierre M. Omidyar suspects about Meetup and he should know, since he founded eBay, as noted by Saul Hansell in The New York Times. What he suspects is that Meetup is like eBay in that it connects people of similar interests. "The early eBay users saw the trade as just an excuse to get to know other people who shared their passion about collecting," he says. "I've always believed," he says, "that helping people connect around a shared passion is good for business and good for the community." It's a belief that suggest that Meetup, like eBay, may also be "a bigger idea than it may have appeared at first."