I think what A.J. Patrick Liszkiewicz says about citizenship at the beginning and end of a talk (about the social game Farmville, of all things), nails it: He told his audience at State University of New York, Buffalo, that "...democratic citizenship has always been a difficult skill to master.... Citizenship requires cultivation...." At the end of the talk, he adds, "The central task of citizenship is learning how to be good to one another." Exactly. I do think it's that simple and that hard. For digital citizenship, you just add the word "online" to the end of that sentence. That's it. Let's do ourselves and our children a favor and not make it one bit more complicated than that.
The thing about this digital age is that it's holding up a very big, society-wide mirror to our faces nearly 24/7, and what we (meaning all of us) see in that mirror of humanity called the social Web is not always pretty. But it's unavoidably in our faces, so we are in effect being forced to think about citizenship – how we treat one another – in school, on phones, in Facebook, in ClubPenguin or WorldofWarcraft, at work, at home, wherever we commune, more than ever before. Because of this mirror in our faces. There are definitely things that need to be fixed at school, at home, in Facebook, but fixing those procedural, policy, and architectural things won't help much if we don't address the behaviors too. The behaviors, good, bad, and neutral, haven't changed all that much (though school bullying has gone down - see this). What's new is that we are being forced to look at them (and the attitudes behind them) so much, and we are overwhelmed, sometimes traumatized, by what we see. What's bad about this reality is that we think technology – the mirror – is creating the problem and keeping us from solving it; what's good is that the need to be good to one another feels more urgent than ever! [As for what Liszkiewicz says about Farmville (as basically the new chain letter) in the bulk of that talk, don't miss it!]