Using the random node and link generator, I wanted to play with some scaling options to get a feel for what the values all mean. Here we have some basic HTML5 sliders to set ranges. Sorry old IE users. I didn't feel like busting out jQueryUI.
Gravity acts to pull all of the nodes into the center of the view.
Charge is the force acting in between the individual nodes. The Charge Scaling slider applies a proportional weighting to each node based on the number of links it has. Set at 0, all nodes have the default charge of -30.
The Node Scaling adjusts the size of the individual nodes proportional to the number of links it possesses.
Node scaling is very handy in identifying major influencers (the most highly connected) in the graph. Increasing the gravity and charge scaling together help impose greater structure to the graph display.