MapEquation.org by Daniel Edler and Martin Rosvall.
From the “about” page:
What do we do?
We develop mathematics, algorithms and software to simplify and highlight important structures in complex systems.
What are our goals?
To navigate and understand big data like we navigate and understand the real world by maps.
Suggest you start with the Apps.
Very impressive and has data available for loading.
You can also upload your own data.
Spend some time with Code and Publications as well.
I first saw this in a tweet by Chris@SocialTexture.