What does it mean that hub nodes are high-value concepts?

Nodes with many connections are core concepts that deserve extra attention.

Example: Open your note graph and sort by link count. The top 5% of your notes — the ones connected to dozens of others — are your hub nodes. In a Zettelkasten of 500 notes, roughly 25 will have ten or more links. These aren't your longest notes or your most polished ones. They're your most connected ones: 'feedback loops,' 'mental models,' 'cognitive load,' 'second-order effects.' They are the concepts you keep returning to because everything else touches them. Lose one of these nodes and dozens of connections go dark.

Try this: Export or visualize your note graph. Identify the 5 nodes with the highest link count. For each one, ask: (1) Is this note well-written enough to deserve its centrality? (2) Does it accurately represent what I currently understand about this concept? (3) Are there connections it should have but doesn't? Upgrade at least one hub node today — rewrite it, add missing links, or split it if it has grown too broad. Your hubs are load-bearing walls. Inspect them.