Assume the distribution problem to be solved, in that people can now easily and reliably get the complete reputation information on an identity that interests them. What extensions to the basic system can be made to make it more useful? What will these extension do to the usability of the system? I think the most interesting extension would be to make reputations that apply only in one realm, a realm being some online community, whether that community consists of a single mailing list (Cypherpunks) or several lists, newsgroups (firewalls, bugtraq, comp.security.unix), or even a larger area, perhaps compromising mail, news, www, other interactive service. Clearly, there is some overlap between some realms (security, cypherpunks, hackers). A good reputation in one area might carry over into another, or it might lead to a negative reputation. This effect will probably arise spontaneously from the webs of interaction. Initially, I was going to propose that it be somehow formalized, but now I see that it will arise on its own accord, given a sufficiently flexible and strong system of distributing digital reputation capital on the net. This does require that negative opinions be made possible, not just low opinions. If Charlie can say "I disrespect David 90% of the time. /s/ Charlie 1 sept 94" and those opinions can spread the same way as positive ones, then most of the useful interaction between groups is possible in a decentralized, out of control sort of way. I've sort of assumed in other places that negative opinions were possible, I just wanted to explicitly state it. Another potential extension would be the addition of more varying formalized opinions than the formalistic "I respect/disrespect..." that I've been basing this on. This also has the possibility of just taking way too much work, but has the possibility, with careful design, to be a very useful tool. What if Alice can say "I think David is a fanatic. I also think David is a windbag." and she says these things in such a way that they can be automatically responded to by software? This would require a carefully chosen list of opinions that the system would support. If you had too many opinions, then the system would be worthless, because, in all probability, people would pick different descriptors, and the information would not correlate into anything useful. The list could probably be fairly short, allowing for terms like windbag, funny, fanatical, reasonable, knowledgeable, trustworthy. That would greatly expand what you could say (or hear) about someone in a simple digital format for automatic scanning and filtering. The inclusion of terms like trustworthy or reliable could act as the basis for some business. A set of 'reliable' endorsements stretching back 20 years would make me much more comfortable with a remailer business than one that sprung up yesterday and is now well respected by 300 federal agents. None of these endorsements need be formal "I'd do business with them again" statements, the objective is to give an idea of who is thought of well, and who is not. With the addition of an encrypted open books protocol then people could automatically get an idea of what businesses are stable, and liked by their customers. I've toyed with the idea of being able to rate personalities this way, which would be useful at times, since there reputations do exist in the personal world as well as the professional. But any system of personal reputations would fail, because bad mouthing someone with a digital reputation is an open act. Very few people would talk about Alice in a negative light if they know she will hear about it. And even if they do want to, there doesn't need to be an automated system to make it easier. However, this does raise the interesting idea of a private reputations system. If a group for one reason or another wants to build a reputation service that is closed; in who may add to it and who may access it, would they be able to? It would probably be fairly simple. The slander program could be modified so that no one who didn't already have some reputation capital could be discussed. Using a system that A useful bit of reputation capital can not be anonymous, although it can be pseudononymous. If it is anonymous, there is no way to give it weight. Cooperative protocols for undeniable digital signatures could probably be designed and made workable. However, I would expect that it would be far too much work to run. I prefer to design a system that requires much less effort. If you want to protect your privacy while participating, work under a nym. There you have it, an outline of a system for possibly efficient, decentralized digital reputation capital. A bunch of extensions that may or may not work. How to distribute is addressed, but needs more work, and probably a prototype. The big question in my mind is how to get people to feed enough information into it to seed the system? Once it gets started, it will run for a while on slow growth, and then explode at some random point. (Probably right after a serious design bug is discovered. :) After it explodes in terms of use, it will be self-perpetuating because of its usefulness. Please feel free to comment on what wouldn't work. How could the system be extended to make it more useful? It might be that building something would be the best way to answer these kinds of questions.