It took some playing, but I finally figured out how to add parameters to a node, which is a fantastic feature. However, they have some big problems (other than being difficult to find):

1. Booleans don't reset - I add a yes/no parameter to a node, and although it's not checked, the node displays "Yes". Checking its box does not change this.
2. Date are treated as bool - I created a Date param named "birthday". It presents a checkbox, and shows "Yes". I can't reproduce the problem, though.
3. Clicking the name dropdown clears its content, so I can't go back to fix a spelling error before adding.

Beyond this, if only there were a way to make these parameters behave as tags, so I can search for nodes having certain values.