As a GNU/Linux and GNOME guy, I absolutely love Tomboy, a little notes application with one incredible feature: autolinking to note titles. This really simple feature allows me to take notes on anything and everything that interests me in a way that is very much aligned with the way I think -- one note links to another in a 400+ note "mesh" or network. I can jump from topic to topic with a click, and organise things the way I think about them. More interestingly, Tomboy allows me to find links between topics that I might not otherwise have considered.
For example, my note on cryptography starts like this:
cryptography: From Greek κρυπτός, (kryptos) "hidden, secret"; and γράφειν (graphein) "writing" (or cryptology, -λογία, (-logia), "study", cryptography is a branch of information processing which studies techniques for secure communications over an untrusted channel, and of "cracking" such communications.
That one paragraph contains a bunch of hyperlinks to other notes: "writing", "study" and "techniques". So I jump to one:
techniques: "Techniques" are a form of human augmentation that don't require tools, only mental constructs i.e. learning.
... and find subsequent links to "human augmentation", "tools", "learning". Combined with the handy "what links here?" tool, I can quickly browse around, jumping from note to note. It's even more useful when taking notes, as that's when the hyperlinks appear -- do I need to research Apache Kato, or have I already taken a note on it? What does OSGi stand for again?
So very useful. Naturally I was happy to see that Tomboy was available for Mac ... but then disappointed when it didn't work for me. But it does now!