Adding an event listener should look like this:

// a shortcut to the Events class
var Events = MindFusion.Diagramming.Events;

// add the listener
diagram.addEventListener(Events.nodeCreated, onNodeCreated);

The current version supports only a small subset of the events available in the desktop controls:
http://www.mindfusion.eu/onlinehelp/jsdiagram/index.htm?T_MindFusion_Diagramming...

There aren't any official Tag or Name properties, but since JavaScript objects are implemented as hashtables, you can add whatever fields you need just by assigning to them:

node.tag = "my tag"; // adds a tag field

or

node["tag"] = "my tag";

Currently there's only the LinkShapes behavior implemented internally. If you need something like DoNothing or Modify, we can add it next week.

I hope that helps,
Stoyan