Gephi’s a graph visualization and analysis toolkit. I’ve used it a few times and am consistently disappointed by its poor UI and limited capabilities.
Gephi Lite is a new online version. So far it runs a lot faster and feels snappier. It’s more limited in some ways but also has two features Gephi sorely needed:
I’m not sure if this is will be useful, but it seems like it’s in active development so probably will get better over time.