Google buys Metaweb.

I read this headline today, and the first thing I wondered was, who is Metaweb?.

And I found this cool video. It looks very promising, very top view and a lot of pixie dust but I'd be interested to know how this actually works.

Now how do these magically connected entities actually work?
source - http://www.kurzweilai.net/google-buys-metaweb-the-one-company-that-could-revolutionize-google-search