There's no reason why one couldn't build a comparable model for mail, with the SMTP speciality service provider offering "SMTP transit" to a base of trusted customers. This comparatively small number of SMTP speciality provider would then maintain good relations ("peerings") with the comparatively small number of major ISPs. Oh wait -- there are a variety of folks who are already specializing in doing that sort of thing -- it's just that most folks don't need to buy that sort of service (yet).
While this could work, we are mixing a format and content type that is not security sensitive and is used to carry point to multipoint messages (forums?) and media (NNTP), with a format and content type that is highly sensitive, and is generally used to carry point-to-point communications which may contain things like personal or financial information (SMTP). I am not sure any level of security would make me feel good about passing my emails through a 'peering .. core' of SMTP relays. However, if we do go in this direction, I plan on firing up my old copies of BinkleyTerm. FIDO and NetMail may be a good place to start :) (Did I just date myself?) -- Alex Rubenstein, AR97, K2AHR, alex@nac.net, latency, Al Reuben Net Access Corporation, 800-NET-ME-36, http://www.nac.net