In a zettelkasten, the ideas that attract the greatest number of links are the most useful ones. The reasoning is straightforward: every link to an idea is created at the moment the thinker finds that idea worth referring to while developing or connecting other thoughts. A high link count therefore directly reflects how often the idea has been actively drawn upon in real knowledge work. This repeated referral serves as concrete evidence of the idea’s practical value—ideas that are rarely or never linked simply do not prove themselves useful in the ongoing process of thinking and note-making. Consequently, the density of incoming links functions as an empirical indicator of an idea’s overall usefulness within the system. The more an idea is linked to, the more it has demonstrated its worth as a reliable and frequently consulted building block.