From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/49775 Path: main.gmane.org!not-for-mail From: Raja R Harinath Newsgroups: gmane.emacs.gnus.general Subject: Re: GroupLens (gnus-gl.el) Date: Sun, 02 Feb 2003 11:29:38 -0600 Sender: owner-ding@hpc.uh.edu Message-ID: References: <4nlm161ks2.fsf@lockgroove.bwh.harvard.edu> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: main.gmane.org 1044206952 6734 80.91.224.249 (2 Feb 2003 17:29:12 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Sun, 2 Feb 2003 17:29:12 +0000 (UTC) Return-path: Original-Received: from malifon.math.uh.edu ([129.7.128.13]) by main.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 18fNux-0001iZ-00 for ; Sun, 02 Feb 2003 18:28:32 +0100 Original-Received: from sina.hpc.uh.edu ([129.7.128.10] ident=lists) by malifon.math.uh.edu with esmtp (Exim 3.20 #1) id 18fNwK-0006K6-00; Sun, 02 Feb 2003 11:29:56 -0600 Original-Received: by sina.hpc.uh.edu (TLB v0.09a (1.20 tibbs 1996/10/09 22:03:07)); Sun, 02 Feb 2003 11:30:53 -0600 (CST) Original-Received: from sclp3.sclp.com (sclp3.sclp.com [66.230.238.2]) by sina.hpc.uh.edu (8.9.3/8.9.3) with SMTP id LAA10574 for ; Sun, 2 Feb 2003 11:30:42 -0600 (CST) Original-Received: (qmail 11647 invoked by alias); 2 Feb 2003 17:29:40 -0000 Original-Received: (qmail 11642 invoked from network); 2 Feb 2003 17:29:39 -0000 Original-Received: from mail.cs.umn.edu (128.101.32.202) by 66.230.238.6 with SMTP; 2 Feb 2003 17:29:39 -0000 Original-Received: from bose.cs.umn.edu (bose.cs.umn.edu [128.101.35.195]) by mail.cs.umn.edu (Postfix) with ESMTP id 1AFD911319 for ; Sun, 2 Feb 2003 11:29:39 -0600 (CST) Original-Received: by bose.cs.umn.edu (Postfix, from userid 818) id C95073269; Sun, 2 Feb 2003 11:29:38 -0600 (CST) Original-To: ding@gnus.org In-Reply-To: (Lars Magne Ingebrigtsen's message of "Sun, 02 Feb 2003 01:24:30 +0100") User-Agent: Gnus/5.090014 (Oort Gnus v0.14) Emacs/21.3.50 (i686-pc-linux-gnu) Precedence: list X-Majordomo: 1.94.jlt7 Xref: main.gmane.org gmane.emacs.gnus.general:49775 X-Report-Spam: http://spam.gmane.org/gmane.emacs.gnus.general:49775 Hi, Lars Magne Ingebrigtsen writes: > Raja R Harinath writes: > >> But, GroupLens is not supposed to be a moderation system. It is >> supposed to find people who appear to have opinions similar to yours, >> and weights the score based on that "closeness" criterion. >> >> It is thus less likely to be poisoned -- unless you are poisonous too :-) > > It's a more subtle tool than, er, "flat" moderation, but it's still > pretty easy to poison But the subtlety is of the same kind that makes bayesian filtering work. The larger your corpus of ratings, the more resilient to poisoning. The poisoner has to put in more work to get to you, and he'll only get a small payoff for all that effort (fewer people reached for amount of effort expended). > (unless you use some kind of authorization system, or keep it "in > the family"). I think the issues here are * make sure that submitted ratings are credited to right person (simple PGP signatures) * make sure that the database maintainer is trustworthy (unlike Amazon.com ;-) Bogus data will be easier to ignore, since it'll be hard for that data to be "close to" good data. > Hacking up a system that would inject a gazillion fake profiles that > would make it likely that your important MAKE VIAGRA NOW messages > rate highly isn't particularly difficult. Probably. But, if none of them is "close", that's not a problem. And, each time you come near a poisoned profile, you can distance yourself from it with your own ratings. - Hari -- Raja R Harinath ------------------------------ harinath@cs.umn.edu