There is one clear lesson from Digg’s sale: the technology that powered a once-massive social network is worth about $500,000. All the rest of the value derives from the people that use it. Though scaling is tough, any developer in the world can build some profiles and let people connect up. It’s an act of genius — or an act of God, by which I mean luck — to design a site constitution that makes people want to build their online lives at your URL (or in your app). Social networking companies are not technology companies as much as they are community companies.