My hunch is that people often affiliate with causes online for selfish and narcissistic purposes. Sometimes, it may be as simple as trying to impress their online friends, and once you have fashioned that identity, there is very little reason to actually do anything else.

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

As befits Silicon Valley, 'big data' is mostly big hype, but there is one possibility with genuine potential: that it might one day bring loans - and credit histories - to millions of people who currently lack access to them.

Sleephackers go to bed with sensors on their wrists and foreheads and maintain detailed electronic sleep diaries, which they often share online. To shift between sleep phases, sleephackers experiment with various diets, room and body temperatures, and kinds of pre-sleep physical exercise.

A lot of the geeks in Silicon Valley will tell you they no longer believe in the ability of policymakers in Washington to accomplish anything. They don't understand why people end up in politics; they would do much more good for the world if they worked at Google or Facebook.

I used to work for an NGO called Transitions Online, and I was their Director of New Media. I was a very idealistic fellow who thought that he could use blogs, social networks and new media to help promote democracy, human rights and freedom of expression.

Look at something like cooking. Now, you would hear a lot about smart kitchens and augmented kitchens. And what do those smart kitchens actually do? They police what's happening inside the kitchen. They have cameras that distinguish ingredients one from each other and that tell you that shouldn't mix this ingredient with another ingredient.