In part, slacktivism is what happens when the energy of otherwise dedicated activists is wasted on approaches that are less effective than the alternatives.

Someone ought to publish a book about the doomsayers who keep publishing books about the end of publishing.

I draw a distinction between freedom of the internet and freedom via the internet. In the first case, it's making sure cyberspace is not over regulated and people can say what they want without fear of repercussions. But that's different from this freedom via the internet notion, which is often touted by all sorts of conservatives and neoconservatives who want young people in the Middle East and elsewhere in the world to use Facebook and Twitter and then go oppose their governments.

Social media's greatest assets - anonymity, 'virality,' interconnectedness - are also its main weaknesses.

If China's expansion into Africa and Russia's into Latin America and the former Soviet Union are any indication, Silicon Valley's ability to expand globally will be severely limited, if only because Beijing and Moscow have no qualms about blending politics and business.

The Egyptian experience suggests that social media can greatly accelerate the death of already dying authoritarian regimes.

The decentralized nature of online conversations often makes it easier to manipulate public opinion, both domestically and globally. Regimes that once relied on centralized systems of media control can now deliver ideological messages more subtly, with the help of little-known intermediaries like anonymous commenters on websites.