The problem with today’s Internet, driven less by text and hypertext (hyperlink-enriched text), is that it not only shares many of TV’s ills but also creates new ones. The difference between traditional television and the form of TV that has reincarnated as social media is that the latter is a personalized medium. Traditional television still entails some degree of surprise. What you see on television news is still picked by human curators, and even though it must be entertaining to qualify as worthy of expensive production, it is still likely to challenge some of our opinions (emotions, that is).

Social media, in contrast, uses algorithms to encourage comfort and complaisance, since its entire business model is built upon maximizing the time users spend inside of it.

This is an argument I've been wanting to make ever since having read Postman. (I still would like to sit down and do a thorough case study of a bunch of media and expand on this idea more.) It seems that a lot of the people who invented the Internet/the World Wide Web are academics or otherwise people who spent a lot of time thinking about information (see: email and HTTP; also all the stuff MIT and Berkeley did). Conversely, social media is predominantly used by/created for "normal" people who grew up/spent a lot of time immersed in TV as "the medium" for receiving information--and the difference between those two mindsets shows up in the disparity between what the Internet was imagined to be and what it is nowadays.

Let me be clear, though: I'm not saying that all of social media is bad, or that good things haven't come from it--far from that. Change is rarely all good or all bad, and the academic dream of the internet is far from perfect as well.

EDIT: see also http://www.newyorker.com/magazine/2007/12/24/twilight-of-the-books