The facebookification of the Internet brings with it a stupidification of the content that people produce and share.
The old web was about blog posts (long, though-out pieces of writing) which automatically form links to each other (through trackback) so that a conversation can emerge without the need for a centralized service.

Trackbacks are awesome! For example, I can make this post appear on quora if I embed some javascript (their embed code) which will ping the quora server:
Read Quote of Ivan Savov’s answer to Machine Learning: Does Topic Modeling need a training stage when using Gibbs sampling? And why does it work? on Quora

We need to cherish this kind of distributed technology, because it is the way out of the walled gardens. They are the living proof that you can have social without central.

LDA, BTW, is short for Latent Dirichlet Allocation which is a powerful way to classify documents according to the topics they contain.