Ian Bicking: the old part of his blog

Bayesian Dark Side

(Looking for Guidance, Navigation, UI?)

Bayesian filters are neat. You can do more than just filter spam with them, of course, they are a general trainable filtering tool, simple but effective. They are old-school AI (i.e., the AI we actually use) -- they don't seem intelligent, but if they get the job done...

But as we all have learned from the movies, AI has its dark side. It occurred to me that Bayesian filters can have their dark side as well -- along with whatever other techniques we create to deal with spam. What if we don't control the filtering for ourselves, what if someone controls the filtering for us, be it the Great Firewall of China or some other censorware? Censorware has always been bad in spirit, but the consolation is that it seems to be pretty bad in terms of effectiveness too. Blacklists and keyword blocking don't work well, especially if people are actively working to foil you with proxies and red herrings. Which are all issues that spam filters have had to deal with. As the spam filters become better at this, it's only a matter of time before the political filters catch on too.

I would imagine Bayesian censorware to work by having trusted people classify randomly sampled pages (as collected from actual visiting patterns). But unlike a blacklist, a well-trained classifier can use its knowledge to extrapolate on the classification of new pages. Unlike a keyword classifier, it is harder to foil with slang. (Though a Javascript compressor would probably confuse the heck out of it)

I find this troubling, because I know there are people out there actively working on just this sort of thing, and I'd hate to see them succeed. (Thankfully spammers are also hard at work to get around our attempts at classifications -- spammers for free speech!)

Created 25 Nov '03
Modified 14 Dec '04


Check out the book Republic.com by cass sunstein for a terrible picture of the filtered future...
# Douglas F. Calvert

# Douglas F. Calvert