"Now clearly, if people are going to head to Facebook for their daily dose of real-world news then mankind has got itself some massive problems. But if people are going to Google for news and are still only seeing a one-sided view of the world which just so happens to coincide with what they already believe is that really the ‘best’ result? On the face of it, it might seem to be a ‘good’ result from the user’s perspective – but is it for the greater good?"

The Ethical Issues of Personalisation Online | SEOmoz