I found the comparisons between then the social networks of Latitude and digital social networks the most interesting. The failure of Latitude seems to be in (of course, perfect) hindsight due to the differences in cost between digital and "human" social networks. To support Latitude, the costs had to be raised far higher than it's user could support. Facebook of course just makes you pay with your eyeballs and your privacy. Both of which are evidently less dear to us than the cash in our wallets.
I can't help but take the human social network as an organization idea farther. I mean it in the best possible way when I point out that every time I go to church there is a point in time in which everyone is asked to give what nominally should be a significant amount of their income to the church to keep it operating. ( Not to mention the sermons we sometimes get could put NPR to shame...) All these networks also need funding to survive, this is not a problem that was unique to Latitude, but an organizational restraint that all social networks that rely on the "sneakernet" primarily instead of the internet face. And, it's one that they've solved.
The issue is trying to incorporate normal startup methods of monetization, or attempting to gather users in a typical software startup way before you even try to monetize. Facebook could do this because the cheapness and "distance" of online behavior makes it simple, but as illustrated in the article, physical space is expensive and people are messy creatures who just soak up time being dealt with (I wonder how much damage or wasted time "jukebox-incidents" caused on a regular basis). Human social network startups -- if such a class exists, would be better served in my mind by copying how other well established networks such as churches spread, giving up control of that spread and monetizing that growth instead.
For instance, Latitude could of taken their most dedicated participants, such as the author of this piece, and given them (perhaps a minimum amount of) training in creating their own network and allowed the to go out as "seeds" into other neighborhood and cities where they would create their own "secret societies". Then, sell digital services, supplies and consulting to these new operators. I would characterize it as catalyzing an organically spreading human experience and profiting off the demand created by that spread instead of centralizing an experience, homogenizing it and profiting off how easily accessible the information from that experience is.