It never ceases to amaze me that so many people can be so wilfully oblivious to an obvious fact: The only thing of any value that Facebook possesses is your personal information. The only way it can make money is to violate your privacy.

How many times does Facebook have to get caught carving a new hole in your privacy with each new feature? Facebook is not your friend, but you can't unfriend Facebook. Even if you're not logged into Facebook, it's tracking you; and often you don't even have to have an account to be tracked, if they can somehow plant a cookie on your browser.

You mentioned something really insidious, bowser: Facebook authentication. I could integrate the HabitableZone's login system with Facebook's, as you've seen, and oh it would be so convenient for everybody, and drag in traffic from Facebook, maybe. A billion new Zoners. But we'd become another node in Facebook's network, another monitoring station on the lookout for Facebook cookies and another trap that'll try to plant cookies on the as-yet-uncontaminated.

By the time you see that little "F" icon on a page, it's too late, you've been logged by Facebook. There's no opt-out. Every Facebook icon and invitation to like something is a sensor in the Facebook tracking network. Actually clicking one of those things is just the cherry on top that adds to your Facebook dossier "and gullible, too".

I have to say that I think Tom's advice is an ineffective palliative, because it just puts you in an arms race with the 800 million pound gorilla. You don't get to set your privacy just once, you have to continually monitor it and reset it every time Facebook introduces a new feature with a new privacy hole. They'll win that game, if not today, then someday.

I think the problem is intrinsic to a digital economy that's managed to grow to epic proportions based on the economic sleight-of-hand of paying for everything with advertising. That's why there's a market for personal info in the first place. Without advertising to inject money into a three-sided relationship between content providers and the audience, nobody could ever grow to the size of a Facebook or Google just by moving bits around. They'd actually have to produce something of value to consumers, instead of advertisers.

That's not to say that there could be no social networks without advertising. But it means that the architecture would be different.

We know from long experience that communities of around a hundred people are optimum, and in the real world we scale up to continental societies by hierarchically aggregating the basic social unit: neighborhoods in cities in counties in states in nations. Social networks would have emerged on the Internet organically just as in the real world, by interconnecting small sites like the HabitableZone into bigger networks of related interests...say, spaceflight Web sites, for example. Without advertising, instead of one elephantine Facebook, there'd be a million small community sites, connected together and streaming socially, but also intimate and local when it counts.

I'm not so sure that Facebook will prevail in the long run. My alternative model isn't entirely imaginary...I plan to add inter-site networking to this software we're using, to allow the university to interconnect with affiliates to create a larger academic network. This alternative model is based on open-source software and is dirt cheap to set up and operate, so it may yet turn out that thousands of people can cobble together a safer and more ethical alternative to the Facebook juggernaut.

I think I'll be playing the Long Game until the day I die ;-)