Amongst email marketers and email service providers, the hot topic of the moment is email authentication.
Email authentication as defined by Wikipedia
Ensuring a valid identity on an e-mail has become a vital first step in stopping spam, forgery, fraud, and even more serious crimes. An essential second step will be Ensuring the entity has a good reputation. Unfortunately, the Simple Mail Transfer Protocol (SMTP) that handles most e-mail today was designed in an era when users of the Internet were mostly honest techies who expected others to be equally honest.
A recent article by ClickZ author Kevin Newcomb, gives an overview of some of the options being adopted.
This is a useful article either for serious email marketers, or those wanting to understand direct email marketing and how TH UK have to follow to provide excellent email marketing services.
Another great overview here from Mark Brownlow Email “authentication for marketers” http://www.email-marketing-reports.com/emailauthentication.htm