Quite a few years ago, I read a wonderful book about unintended consequences. It was an excellent narrative and collection of case studies surrounding good ideas, gone very bad. Items like Prairie Grass overcrowding, the Tacoma Narrows bridge, bio-engineering that ‘slipped’, etc. The recurring theme in the book was that complex systems — which is to say most natural systems and quite a few technological ones — interact in unforseen ways when a new stimulus is introduced. Sometimes, it isn’t a new stimulus at fault, but one that was omited from the model, or perhaps the magnitude of the stimulus was not properly anticipated.

The book is Why Things Bite Back : Technology and the Revenge of Unintended Consequences by Edward Tenner, (Not Teller!), ISBN 0679747567 and I reccommend it to anyone who wants to dive into this sort of thing. Along these lines, I found a fascinating reading list for Crisis and Disaster Management.

Whatt does this have to do with e-mail and SPAM? It turns out that a mailing list that I administer for an open-source SIP stack project (reSIProcate) has had a higher than normal bounce rate for the last week. The reason? Some MTA administrators have started rejecting e-mail that contains Chinese and/or Korean characters with a rather lofty and rude:

      550 Sorry, noone speaks chinese here (in reply to end of DATA command)

Why is this a problem? There’s the obvious xenophobic slant to it, but it is more interesting to consider a case where someone (S) is subscribed to a mailing list from a domain that employs this technique, and then consider what happens when an asian list subscriber (A) posts multiple messages (in English) to the list over the course of a rapid discussion thread. The messages from A are delivered to the poorly configured MTA and they bounce because (A) signed his name in his native character set. (Additionally, A has native characters (non US-ASCII) in his display name in the mail headers). These bounces happen immediately and after A posts 5 messages to the list, S is automatically suspended for excessive bounces. This happens for ALL S-like subscribers behind broken MTAs.

Wow, unintended indeed!