This looks like being a thoroughly excellent event at The Royal Society, featuring Tim Berners-Lee and Albert-Laszlo Barabasi.
An extremely addictive bit of fun with small world network theory as applied to music.
Six degrees of separation as applied to Wikipedia articles. Read on to find the Kevin Bacon of Wikipedia pages.
It turns out that the brain is a scale-free small-world network in a state of self-organised criticality. Just like the internet.
Duncan Watts works at Yahoo Research? I had no idea! Ironically, it was Gladwell's Tipping Point that first led me to Watts' work.
A lovely visual of contacts of your Twitter contacts, exploring those six degrees.
The Dunbar number gets bandied about a lot in conversations about social networks these days. Here's the original paper that shows the research behind the oft-misused term.