We’re all embedded in vast social networks of friends, family, co-workers and more. Nicholas Christakis tracks how a wide variety of traits — from happiness to obesity — can spread from person to person, showing how your location in the network might impact your life in ways you don’t even know.

Great talk about the intrinsic value of the social networks within which we all reside. If you can get past the first few minutes when he’s almost shouting and you keep reminding yourself its not an elaborate new advert for T-Mobile, it’s very interesting. It also partly explains why everyone who works with us is slim and in a perpetual state of happiness.