What about the ability to form a group of nodes to some kind of section or "cloud"? This would be great to make a distinction between different nodes that is seen visually. Like, I'm researching the works of an author and form a cloud with all the nodes that's linked to him. And in that cloud I make another one with on of his books and then another one in that cloud with the characters in his books, another one with the places, etc. This would would be great to make it more structured, and somehow see directly which part of my brain I'm looking at.

It could be sorted by tags, so that for example "Robert Jordan" is one cloud, and then "Robert Jordan" + "Wheel of time" is another cloud. If this could be done with different colors or "type of clouds" it could distinguish the data in the brain really well.