In addition to their 'do no evil' motto, Googlers have always been guided by another, much less explicit philosophy: 'computational arrogance.'

The implications are clear: Facebook wants to build an Internet where watching films, listening to music, reading books and even browsing is done not just openly but socially and collaboratively.

Personalization can be very useful in some contexts but very harmful in others. Searching for pizza online, it's probably OK to keep showing the same pizza shop as your No. 1 choice. I don't see any big political consequences out of that.

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

There is no doubt that the Internet brims with spamming, scamming and identity fraud. Having someone wipe out your hard drive or bank account has never been easier, and the tools for committing electronic mischief on your enemies are cheap and widely accessible.

Revolution may not be pro-Western or democratic.

A vibrant civil society can challenge those in power by documenting corruption or uncovering activities like the murder of political enemies. In democracies, this function is mostly performed by the media, NGOs or opposition parties.