Here’s the idea. A cryptographic key is embedded in each message binding it to the sender’s Domain Name System listing.

Yahoo claims it will help even if only a few big ISPs roll it out. techdirt observes that, at the very least, it’d make bad guys easier to track.

The code will be released so (hopefully) all spam controllers add it to their armouries.

Of course, it can’t save you if a spam virus hijacks your system…

See for yourself at The Economic Times.