There's a new kid in town.  It's called "Dmail", and is the brain-something of one Peter Jackson, of Dorchester, Dorset, UK.

The concept is simple:  Dmail is a closed system available only to subscribers, who have to log in to get their dmail messages.  Nobody outside the system can send them spam.  Of course, nobody outside the system can send them any email at all.

Jackson admits that it is a niche market, and only those interested in a closed - indeed completely buttoned down system - will be interested.

Techworld's Peter Judge calls it a "crackpot scheme", but on webscreen it doesn't sound completely insane.  From their website, at http://www.mydmail.com:

"Welcome  to dmail™ a faster, safer alternative to email which is  accessible from anywhere in the world. dmail™ is digital  mail and does not interact with email. There can be no viruses  or spam.

 dmail™ is fast, with unbelievable capacity for storage and the rapid exchange of music, video, images and documents.

 dmail™ groups can be completely isolated which means even  more security, with no intruders or unwanted guests.

dmail™ is  a closed system so to communicate with someone they must also  have a dmail™ address."

It remains to be seen whether it's D-for-Duh or D-for-Darned-Clever -mail.