Some trust-metric references
All the references listed below link to PDFs, with my comments in italics.

• Weeks, 2001. Understanding Trust Management Systems. Crucial paper for understanding much recent work on trust-metrics. Presents framework, motivates it with examples, and shows PKI can be modelled using it.
• Carbone, Nielsen and Sassone, 2003. A Formal Model for Trust in Dynamic Networks.. Proposes a simple domain- theoretic formalisation of what a model of trust is that provides the basis for some significant later work.
• Twigg and Dimmock, 2003. Attack-Resistance of Computational Trust Models. Synthetic exposition of several trust-metrics that have some degree of attack resistance. Good exposition of Raph's metric, sgives alternate proof of attack resistance by order-theoretic reasoning.
• Moreton and Twigg, 2003. Trading in Trust, Tokens, and Stamps. Proposes system for adding trust trading to trust-metrics by stamps, and argues for advantages of this system. Interesting for Advogato: could provide a more principled means of bringing in new members than just rejigging weights.
• Ziegler and Lausen, 2005. Propagation Models for Trust and Distrust in Social Networks. Motivates criteria for success of trust-metrics when applied to social networks, including attack resistance. Proposes a new algorithm, which they call Appleseed and which is based on the spreading activation technique, which they compare to Raph's version. This work is based in part on Ziegler's PhD thesis, Towards Decentralized Recommender Systems.

I'm curious as to the origin of Raph's talk of "good", "bad", and "confused" nodes. Is it his novel usage, or did he get it from elsewhere?

I'm amused also to read references sections that cite Raph's abandoned trust -metrics thesis as if it was a successfully defended one. Folks who run into the thesis he did write will no doubt conclude he is one of the select few who wrote two PhDs concurrently...