Spam could prove cripplingly expensive for companies whose staff use a wireless internet connection that charges for the amount of data received, such as those using a GPRS cellphone link. The answer, says Nihon Digital of Tokyo (GB 2382190), is for every user to have several email addresses, only one of which is published. If mail arriving at the published address comes from a source on an “approved” list, it is sent straight through to the wireless appliance.
All other mail is shunted to a secret address, where a server checks whether other people are receiving similar messages. If they…
