The value of a social network is defined not only by who's on it, but by who's excluded.

It's interesting to see the lament of each generation overwhelmed by the next new tool. I can show you passages from scholars of Germany in the 1480s lamenting the fact that they are overloaded with all this stuff to read because of the printing press.

We invent our technologies and then we turn around and use our technologies to reinvent ourselves as individuals, communities and cultures.

There is reason to be scared. Look at what has happened with fundamentalism - this is a reaction against modernity. It happens to be cloaked in religion, but these are people saying enough is enough. It's happened again and again through history. The good news is that modernism has always won.

I think it is just a matter of time before we have literal ghosts in the machine so you can create an alter ego of yourself that learns from your social experiences and extends a life even if you're no longer in the game or you are no longer alive.

This new world of personal media - the Web, the Internet and et cetera - not only delivers the world to your living rooms, but everywhere. And we get to answer back. And we're expected to answer back.

I'm actually an optimist about what lies ahead. Are wikis reliable? It depends on the specific business. Is Wikipedia reliable? You bet. Wikipedia is a researcher's dream.