Marc Stiegler, author of Earthweb, just published An Introduction to Petname Systems which discusses Zooko's Triangle:

Zooko's Triangle [Zooko] argues that names cannot be global, secure, and memorable, all at the same time. Domain names are an example: they are global, and memorable, but as the rapid rise of phishing demonstrates, they are not secure. Though no single name can have all three properties, the petname system does indeed embody all three properties. Informal experiments with petname-like systems suggest that petnames can be both intuitive and effective. Experimental implementations already exist for simple extensions to existing browsers that could alleviate (possibly dramatically) the problems with phishing. As phishers gain sophistication, it seems compelling to experiment with petname systems as part of the solution.

I first met Zooko a long time ago. I was working on a demo project for Deutsche Bank using Digicash's ecash system. The setting was one of these very German, very stiff business meetings, where you didn't expect anything interesting to happen. He was clearly uncomfortable wearing a suit and I was wearing jeans and a faded blue D.E.A. jacket. Ignoring the bankers we had some meaty geek talk about cryptography and crypto anarchy. At that time he had just joined Digicash and was enjoying his time in Amsterdam. I visited him there once hoping to walk into the company founder David Chaum, who holds a bundle of patents on cryptographically secure and anonymous cash systems. Unfortunately Chaum was out of town. Zooko later worked for MojoNation and after they shut down, he initiated the Mnet project.

Further reading:

• Zooko's original paper: Names: Decentralized, Secure, Human-Meaningful: Choose Two
• Zooko on multithreading and E
• The E programming language
• CapROS: The Capability-based Reliable Operating System